fare codes?
 

I am new to all of this. My question is about the various letter codes used to describe the type of fare. I have figured out that this is especially important when wanting to either purchase (with miles) or requesting a complimentary upgrade to first.
I am with Delta and Continental. How do I know what fare i am purchasing? I normally purcase directly from the airline site (for the bonus miles) or from travelocity or similar.. If i wanted to purchase a specific type of fair, how to I request that??

One of the neat capabilities of FlyerTalk is the ability to search prior posts by key words. At the top right hand part of the page is "search".

Here are a few threads which should help.

Good luck.
http://www.flyertalk.com/forum/Forum21/HTML/000981.html
http://www.flyertalk.com/forum/Forum1/HTML/001934.html
http://www.flyertalk.com/forum/Forum1/HTML/002934.html
http://www.flyertalk.com/forum/Forum1/HTML/002885.html

thanks