I would have to recommend a little different tactic. Take your 6 gb hdd and install it into your main rig. Disconnect your win drives completely, then install Ubuntu 6.10 on your 6 gigger. Afterwards just swap back and forth in your bios, choose which to boot from.
Reasoning is simple, while your celeron will run linux, the 64mb of ram probably wont allow KDE or Gnome desktops to load. xfce would work, but it can be frustrating if your totally unfamiliar with it.
Your main rig will run it fast, Ubuntu forums have great support, and its simple to install and probably the most stable I've worked with for quite some time.
the page you want.
If you insist on using your older rig then I would try Damn Small Linux, here
. I've never used it, but I understand they packed a lot into a tiny little distro.
Either way good luck with it and enjoy.