Connecting from Vista to MacOS X

Hi guys. I've got some large files on my laptop that my friend would like to have on his Mac. The Mac is running OS 10.5 and is connected to a Netgear router via ethernet. I am using Vista Home Premium on my laptop, and connect via the same router wirelessly. I've tried to find some way of sending him the files via the router, but I can't suss out how to do it.

If I look at the network on my system I appear to be the only thing on it. I've tried entering his local IP into Internet eExplorer, but that doesn't work either. Frankly, I'm stumped.

I've never had to send stuff over a home network before, and I think the fact that I'm trying to access a MAC (which neither of us know how to use, LOL) is really complicating things. I'd really appreciate some help from somebody who is familiar with both systems. Thanks.