Originally Posted by maisam
Should I replace the battery myself or searxh the market bazaar for an expert...?
I would definitely be looking for someone who has this area of expertise. The iPhone's battery, most notably the 2G, can be very difficult to replace. Considering this is also the model that requires the battery to be attached via soldering, I highly suggest someone else does it to avoid further issues.
Just a little anecdote, my friend had a similar issue with his iPhone 2G and decided to replace the battery himself. He got to the stage where the battery required soldering and accidentally short-circuited the mainboard with his solder. He ended up throwing the whole thing out...