Ubuntu Networking :: Sharing Files Over Wireless With Other Computers

I got my somewhat older desktop running ubuntu 9.10 and I'm loving it so far. However a while ago while I was slightly intoxicated I boasted to my roommates that sharing files with this thing should be super easy, since it's linux and all that. Since then I've been trying to set up the desktop as a streaming media server, with no success. I found a pretty good guide on how to get Samba up and running on instructables. My laptop is part of a school domain. Since many of my roommates go to the same university, theirs are also part of that domain.

For those of you who aren't too familiar with Windows (anymore), your computer can either be part of a workgroup or a domain. A workgroup is intended for home networks and makes it easier to share files, which is what I'm trying to do, and what the guide calls for. I've illustrated the problem in the attached image. As you can see both computers connect to the same router. I don't think I really have to explain, but I just figured I should try to be as clear as possible.

My question to you is: is there any way that I can set up the ubuntu desktop, or samba, so that it can share files over the wireless network at home with the computers that run windows and are part of the school domain? I'm guessing I should somehow be able to access the desktop from another computer on the same network if I give it proper access. I just have no idea how to do it or where to look, since almost everything I encounter calls for putting the windows machine in a home workgroup.