FTP apps, Networking, and the Such

I've tried looking through the threads but haven't found what it is I am looking for. I want to run my MBP 2.4 GHz with an FTP server app, and am curious as to which app would be the easiest/ best when working between windows and Mac. I am guessing that there shouldn't be any real problem with FTP.

I have been trying to network my mac running 10.5 with one computer running XP, and one running Vista, and a Mac Pro running 10.4. The macs love each other but the PC's don't recognize the Mac on the network. I've tried setting up workgroups but don't really understand it all that well. I've gone through my file sharing settings on my computer and that of my roommates, and I have made sure to activate them but no dice.

I'm sure I haven't provided enough information and may not know what else people would need to know. So, for those who know something that could help, I welcome the comments.

You can get the Windows PCs and the Macs to talk to each other and share files without any additonal software. My wife's old Dell had direct access to her user account on the Mac and worked like a charm. Here's a page that should have all the details you need to set this stuff up right:
http://www.mac-connect.com/

thanks dude, I'll give that a try.