Newbie Help sharing music with Itunes

I bought a mac book (with 60gigs of spaces) and moved all of my music from my PC to my mac book. However, my girlfriend moved back to Japan for the rest of the year and we want to share music. She has a PC and I just got a pc so we can use the Windows Live File Sharing (it's what we'll have to use).

If there anyway for me to share my itunes library on both my mac and my pc? Or, can I move my library from my mac to my PC? I'm running out of the hard drive space and it would be an easy way to free up space.

When I first got my iMac G3, I moved all of my music on there and connected it to my wireless router via ethernet.

I was able to use iTunes sharing on my Windows laptop to wirelessly access the music on my iMac by ticking the 'enable sharing' box in preferences and configuring my firewall to allow iTunes access to my network.