What size frame?
 

I am 6 foot 6 inches and weigh 240. what size frame should i be on? my trek was just labeled as XL. what about a size in inches and/or centimeters?

Hard to answer. Have you tried to sit on the bike and then look at the frame size? This is definitely the case when your best bet is a visit to local bicycle store.
http://www.lpf.com/adventure/nova-sc...bike-small.JPG

http://www.cowguys.com/jonbike.jpghttp://www.main.com/~plummer/97day7/hugebike.jpg

I would also say to check the LBS. If you are trying to estimate the size yourself, I think the inseam is a more important measurement than your height. You want to check standover clearance on your bike. This also depends on if you want a road or mountain bike, as standover should probably be a couple of inches more on a mountain bike. Of course once you have that measurement taken care of, you need to see what your reach to the handlebars will be, to see how stretched out or cramped up you will be on any particular frame. You can get all kinds of measurements at bike websites, but the best way is to ride the bikes at the shop to see how they feel to you. Good luck!