Running iPhoto & library from an external disk?

Hi,

I'm about to wipe my iBook G4 to clean up the files and make some space by just installing my most often used programs and was wondering if it's possible to run iPhoto from an external hard drive so all the photos and library files would stay on the external disk? I've got a 40 gig hard drive which is already filled up with a bunch of music and pictures and getting the pictures off there would free up about 4 gigs, so I'm trying to make room without sacrificing all the albums I've got going right now.

Any ideas would be great--thanks!