For some reason there's still a lot of confusion about how Leves work, so hopefully a short explanation will clear up the confusion.
First of all, they are indeed called Guildleves, not Guildleaves. It's pronounced like "leave" but it's not spelled that way.
Next, types of Leves. There are two major types of Leves, Regional and Local. Regional are obtained from Piralnaut, the Elezen male in The Mizzenmast, local are obtained from T'Mokkri, the Miqote female who is standing next to Piralnaut.
Regional leves include Battlecraft leves (go and kill X, Y and Z), Fieldcraft leves (go and harvest X, Y and Z) and Faction leves (go and do X for Y faction that likes you) as well as the tutorial Leves, which are just Battlecraft or Fieldcraft leves that must be completed to unlock some basic class abilities as well as advance the start of the story line.
Local leves are (so far at least) strictly crafting, so they are broken up by crafting class.
Each character can "hold" up to 16 leves at a time. These can be leves which have been accepted but not activated, activated but not completed, or activated and then either failed or completed. This pseudo inventory for leves is broken down into groups, 8 regional leves and 8 local leves. You cannot ever receive more leves of either regional or local type, if you have eight already, unless you "exchange" at least one completed/failed leve. I'll talk more about exchanging in a moment, but the important message is you have a limited amount of space for leves.
Keep in mind that the NPCs who give leves have a limited and semi random selection of leves, and this selection refreshes each 48 hours server time. This is **NOT** 48 hours from when you accepted or completed a leve, it is pre determined time each day (I believe midnight in Japan) and it occurs every 48 hours regardless of your actions. Thus, depending on when you take leves, you may be able to complete as many as 32 total leves in a very short period of time, or you may have to wait almost 48 full hours once you have completed your current allotment. To the best of my knowledge there is no way to check within the game to know how close the server is to the designated "reset" timer. Hopefully this is some thing that gets changed before final release.
In order to complete a local leve, you will typically be given directions to a specific NPC who is looking to have some thing or things crafted. Some times you will be given the Leve specific crafting materials as part of initially accepted the leve, and some times you will need to talk to the client first. It's important to note that for local leves, you will NOT craft the requested items using normal materials, only the quest item materials that have been provided for you. This means that when you go to craft these items, you should look for the menu option to use leve items rather than putting your own materials into the synth container. If you don't see such an option during your synth, chances are you forgot to talk to the NPC client first.
One other important note: The recipes for local leves are always valid synthing recipes. If some one gives you a leve to craft cloth pants, pay attention to the materials that end up going into the synthing container when you craft. That same item combination will yeild the same items for you, using non leve materials. This is currently the only known way to "discover" new recipes apart from trial and error, so it is good information to write down in a notebook if you are not blessed with perfect memory.
Regional leves are slighly more complicated. Once you have received a regional leve, you must travel to the large Aetheryte location to which that leve corresponds. For level 1 leves in P3 beta, this means Camp Bearded Rock. For level 10 leves, this means Skull Valley, and for level 20 leves, this means Camp Bloodshore. Once you have arrived at the designated Aetheryte, you will activate it, and select "Initiate Levequest." You will then be given the option of selecting any Leve in your inventory of selected leves, as long as it corresponds to this location. For Battlecraft and Faction leves, you can also select a "size" from one star to five stars, with one star intended for solo players and five stars intended for large (12-15) person groups. Larger leves typically have more enemies, and enemies will hit harder as well.
Fieldcraft leves are generally solo affairs and lack the "star" designations. You simply activate the Leve and then try to complete it.
Regional leves have time limitations to them. From the moment you first activate the leve, a timer will be displayed and begin to count down. You must complete all of your assigned objectives before the timer reaches zero, or you fail the leve. The faster you complete your objectives, typically the larger the completion bonus will be, though the bonus amount is typically small, so there's no reason to rush if you don't feel comfortable doing so.
When you complete the leve objectives, the screen will flash, you will hear triumphant music, and a temporary Aetherial Node will appear. Interact with this node to receive your reward(s) and have your HP and MP refilled to 100%. You can choose to teleport for free back to the camp which originated the leve, or allow the node to dissipate and remain where you are. Note that if multiple people within a party all have the same leve in their inventory, completing it for one player will actually cause it to be completed for all players, which can be a good thing or a bad thing, depending on what your goals are. Just keep this in mind and if you think you're going to be partying to complete leves, consider NOT actually accepting any leves until you know how the group is going to work. You don't want to "waste" leves if the party wants to be able to repeat them for each player in the group (typically to gain more XP).
Leve Exchange: Whenever the 48 hour server window changes, new leves become available at designated NPCs, allowing you to grab fresh leves if you've finished yours, or grab any additional leves that you might not already have. At this time, you'll be given the option to exchange any of your completed or failed leves in order to increase the rewards of any new leves that you might accept. You can exchange any where between 0 and 4 leves for each leve accepted, and the more you exchange the more the reward for the newly accepted leve will increase. Typically this increase will be reflected in the currency rewards (either gil or faction currency, depending on which would be awarded). Exchanging 4 leves can typically boost the rewards of a leve by 50% or more, so it pays to be mindful of which leves will reward which currencies, and how many, before doing any exchanges.
Also note that if your leve inventory is full (8 regional and/or 8 local) you can only accept new leves by exchanging at least one leve to make room for the new one AND if you accept a level which is identical in name to one that you have completed, you will automatically exchange the old leve for the new one.
I hope this covers the basics of leves to the satisfaction of all. If any one wants to add additional information, please post in this thread. If you have any questions I'll do my best to answer them.
Edited, Aug 22nd 2010 4:00pm by KarlHungis