This guy has a brilliant replacement for the instruction manual. Those things are usually written by someone for whom English is a fifth language and are damn near useless.
Right about two years ago I bought a 40GB hard-drive based iRiver MP3 player. It has a few quirks but it's been a workhorse player until recently. The battery hit end of life. First symptom was that it would suddenly power off when trying to do line-in recording. And it went downhill from there. When new the player would go a good six to eight hours on a charge. At end-of-life it was down to between 10 minutes and an hour.
I checked into buying a replacement player since technology has moved along. But to get something of equivalent capacity I was looking at nearly the same price as I paid for the iRiver. Google came thru with a pointer to a battery available on iPods99.com for $29. The confirmation email came along with a pointer to an instructional video for replacing it.
There is the brilliant concept. No indecipherable manual with about a third as many diagrams as you really need, a video. And along with the battery came a teeny phillips screwdriver and a plastic pry tool for opening up the player.