external enclosure....

either one should work..i mean, they're just drives. unless you don't have a USB port, i can't see why you wouldn't be able to use em.

 

it depends on what you're planning on doing with the clone. If you're going to put the cloned HD into your PB then it needs to be the ATA enclosure, not the SATA, as your titanium powerbook doesn't support SATA drives.

If not, then just make sure whatever drive you are buying supports the enclosure. (ie, sata drive goes in the sata enclosure...)

Also, you can't boot from a USB enclosure, so if you want to clone the HD to boot from it, you'll need a firewire enclosure.
Here's the cheapest one i found, but look out for the $10 shipping.

also try macsales.com for enclosures.