Ok, so I've done quite a lot of research and have yet to find a 100% conclusive answer.
I have an 857 Powerbook G4 with a hard dirve that is going to die any day now.
I was looking at an
Seagate Momentus 7200.1 ST910021A 100GB 7200 RPM 8MB Cache ATA-6 Notebook Hard Drive - OEM
Seems like a nice hard drive and good price, but I don't know if it's compatible. It seems to be, but I was hoping someone knew for sure.