My friends phone was stuck in recovery mode and giving me a code 29 when trying to resore it. This is after she dropped it in water. Bought a battery off of eBay and got a bum battery that didn't work and i was unable to contact the seller.
Bought new battery from ifixit and got a workin phone again! The guide was easy to follow and great detail.
Great place to buy parts and learn how to do it all in one place. Highly recommended! Of course not all water damage phones are the battery. Switch batteries with another 3GS first to confirm first. My friend was just lucky!