This is an extract from the email American Airlines sent to me last May:
I am pleased to have this opportunity to explain our decision to add more seats back on our airplanes.
When we introduced our More Room Throughout Coach« product, healthy yields and robust business travel were the norm. ........ Now, however, the marketplace has changed even further. With the record high price of fuel and the continued low fare environment, our More Room Throughout Coach product puts us at a revenue disadvantage to our competitors. ....... However, we will be adding back fewer seats than we initially removed. .... The result is that there will still be more legroom in the coach cabin than there was before February 2000 (when we first began removing seats). ......
On my flight with them 2 weeks ago, I noticed an old 'More Room Throughout Coach' sign still there, but it definitely wasn't the 34" pitch they used to have! Got to say though, it was still a bit better than the Delta flight I took a few months earlier (which was still okay), so it is still probably better than many of the major carriers. I believe the other good one is United Airlines, but I could be wrong since it's a while since I used them.
You might find
www.seatguru.com useful for pitches, seating charts etc. Last year it was telling you about AA's decision when the change was in progress but now because it's done (or so I believed) it seems to have been removed.