Just had to pull mine off to paint my door. Tried to figure it out looking at the pic above and still had problems so I put together a how-to for anyone else that finds this thread in the future.
To remove it:
You have to have a working key as it states above in the other posts. if you don't have a key, a locksmith can make you one if he either comes to you or you bring him your whole glove comparment door.
Latch the catch by pushing it with your finger till it clicks
Insert key with cuts to the right
While applying pressure to the latch, turn the lock counter-clockwise to lock the handle.
TAKE OUT THE KEY TAKE OUT THE KEY TAKE OUT THE KEY TAKE OUT THE KEY !!!!!!!!!
Did you remember to take out the key? YOU CAN"T DEPRESS THE TAB IF THE KEY IS IN.
Turn the door over so that the lock is now at the bottom and release hole is visible.
While depressing the latch, reach into the hole with a pic or small allen wrench to push down on the release tab. If the key is in, the tab will not depress. Use the pic all the way up against the front edge then push down.
Pull slightly on the lock assembly, and the tab will now be on the other side of the front ring. . You will also depress this tab on the other side during reassembly.
Now insert the key to release the rest of the cylinders while wiggling the rest of the lock out. Depressing the lock latch the entire time will help throughout the disassembly and reassembly. This is a pic of the tab that needed to be depressed once you pull the cylinder out enough to clear the ring, without the glove box door.
Here is what it looks like apart
During reassembly remember to keep pressure on the door latch. You can see my thumb holding the latch on the bottom.
and use the key inserted till you get the to the locking tab up against the lock ring, then remove the key before trying to depress the locking tab to slide in the remaining, 1/8 inch.
Very easy to take out once you see what you're going after.
EDIT Jan-2011. I had to finally reassemble my door and install the lock. After bolting down the latch to the door, I was able to insert the key into the lock, then slide the whole thing into the latch assembly without depressing the tab. I did hold the latch to the closed position while inserting it though.