Urgent Help with HD's!

Hey guys,
I have two HD’s and two OS’es. My first HD, is a 20GB, and second is a 80GB.
Windows2k is running on my 20gb, and Linux is running on my 80GB. I really need more space for my win2k os, so I want to be able to use the 80gb HD to save files on. I really need to do this, can someone help me!!!

Thanks in advance