I run my 3GS pretty much 24/7. The almost constant Internet use is beginning to take a toll. Right now I have it stripped back, no extra's sucking power, and I've begun to notice a sharp decline in battery life. And a sharp decline in how long the 3GS holds a full charge. What are my options? Does anyone make an aftermarket battery I can put into my 3GS myself? Will Apple change the battery for me at my local store? Or do I have to, shudder, send it in?