I just found a way to transfer files between my PC and my "Mac" effortlessly via FTP . Maybe it will work for you too. I don't know if I can offer any help if it doesn't work, but here's what I did.
1. Win XP
2. OS X 10.3
3. PPC 0.3pre
4. Internet connection through TAP-Win32 Adapter connection and Analog X Proxy
1. In OS X, go to System Preferences>Internet & Network>Sharing
2. Under the "Services" tab, enable FTP Access
3. Note the FTP server address it tells you that others can now connect to your computer through
4. In Windows, go to "My Network Places"
5. Click on "Add a network place"
6. Choose the "Choose another network location" option in the wizard that comes up.
7. Enter the previously noted FTP server address into the "Internet or network address" box
8. Uncheck the "Log on anonymously" option in the next screen and in the user name box type your Mac user name (this can be found in System Preferences>System>Accounts)
9. Finish the wizard and drop the network place wherever (in your PPC folder, perhaps).
10. Connect and drag and drop files to and from your Mac HD!
For me, it works with the same speed as moving files around on my PC.