14" white iBook G3 - what replacement HDs will work?

I'm internal-HD-shopping for a friend, and want to make sure I know:

What terminology will identify drives I can put in this iBook? I know it's 2.5"--what else should I make sure of?

Also--any kinds that would be better than others?

It's a 14" G3 with Firewire and DVD-ROM. "New" as G3s go.

TIA!

Thanks from both of us! You seem to own a similar machine.

Can this machine boot from an external Firewire drive? (I assume all Macs can.)

Also, does it have USB 1.1 or USB 2.0? (If 2.0 we might boot off that--which Tiger can do I think.)

Thanks!

I think maybe Tiger added USB bootability, but at 1.1 speeds, I think we'll skip that regardless

It looks like changing the HD in this machine is an incredible undertaking with dozens of screws, foil tape, removal of top AND bottom cases, and ribbon cables galore... So I'm considering external boot as an emergency solution.