I know, I know...a real rookie question here. But I can't seem to find an answer in any of the sticky threads.

Is there any means, tool, etc. which can tell you the fare class of an AA flight prior to reserving it on-line? I've been booking a LOT of deep-discount fares (N and O) lately, but would love to know the price difference between these fares and even Discount (H, M, etc.) so as to determine if it's worth the extra $$ to earn more points.

Any suggestions? Thanks in advance.