Hmmm... alright, seems like it either started working or I typoed it before. I still don't see the other PCs in the Workgroup, but I can access them via cd \\ip-addy\shared-folder. Further suggestions?

And hey, thanks for the advices so far.

It's weird, if I look for other PCs or *, in the stupid XP Search thingy, they aren't there. If I type in their IPs though, they become visible...