Which one?
 

I have a g3 slot-loading iMac without a lot of room left. So would I be able to install linux on a external drive, and boot from there? (probably yes, but I'm not sure) If I were to do that, then which distribution should I use?

*edit*Oh yeah, I have no idea about how to work linux*edit*

Well, you could boot from an external disk if your system supports it. I don't own a Mac and have used them very sparingly, so I couldn't tell you anything about the Mac BIOS.

What I would do would be to install a second hard drive into your system and put Linux on there. Since you don't have a lot of expierence I would recomend trying a distro like SuSE or Ubuntu, make sure you get the PPC version and not the x86 version. Both of these distros have excellent support and documentation to walk you through installing and using them.

i dont know about linux far as the binaries go but i know that you can load OSX or OS9 on a external firewire and load off of them and it isnt all that slow

"SuSE or Ubuntu" okay, I'll check that out. Thnx. :)