I'm in the same boat, I have yet to move up to Leopard and my battery is in rapid decline; right now it registers at 27%, although it has been both lower and slightly higher than this within days. It is shutting off without warning with increasing frequency in the past few days.
I suppose it could be the cycles in my case - close to 400, I use it heavily when on the go. (Although I'm not entirely sure what is considered a cycle: is it every time it is fully charged, declines, and then is charged again, even if it isn't fully discharged in between?) But it is still extremely frustrating; perhaps more so since I'm guessing due to my cycles I can't get a replacement from Apple. (I already had my original replaced because it was one of the defective ones.)
Given the volume of complaints, one would think that Apple would be actively trying to solve the problem, and it would seem that the replacement program is one step toward that. But for those of us who might not qualify and are wondering whether it is worth spending $129 on a new battery every six to eight months, this isn't of much solace.
