I have an Ibook G4 with 1.42ghz processor 1.5gb of RAM and a 60gb HDD (only 16 available help with clearing that up a bit would be cool too). Apple says its supported, but i know that I should not have the min req. so I just wanted to check, thanks.
It would work, just might be a bit slower than Tiger. But it's worth it for some of the features. As for the HDD, you can get a external HDD and use it to store your files. If money is an object, you can try burning some of those files to CDs or DVDs (if you have the SuperDrive).
Also, you can use OmniDiskSweeper to find those big files that are on your HDD.