I'm currently using this for 3 month's now and it doesn't give any problem until on a few days ago(Tuesday 9th Feb 2010), when my battery was low and I charged it up as usual. After 2 hours charged it completely, i removed the charger from the phone and used it as my alarm clock.

To my dismay the next morning I got up, I realized that my phone was dead. I tried to power up and nothing comes on. So, I recharged it again, after charging, the battery was full. About 1 or 2 hours I noticed that the battery level dropped slowly and after that it went dead again. I can also feel the heat from the back of the cover. Once I open the cover, the heat was coming from the battery. I was wondering if anyone have the same problem. Its an original battery by AVAXX and it comes with the set of the phone when I bought it. I simply just don't understand how this could happen. I'm not very sure if its either the phone or the battery is giving the problem.       

It could also be an errant program. Especially something using data (3G data connections will heat up the phone and chew through battery power pretty quickly).

I'd suggest doing a full backup, then hard reset and only restore your contacts (or don't restore anything if you can live without it for a day), then use the phone for a day and see how it goes.

I know someone else who recently had similar troubles (sucky battery life and warm phone). He did a full backup, hard reset, then full restore and the problem persisted. Then he tried hard reset without a restore and everything was fine. So he re-loaded everything manually and it's working great again.