accessing windows computer from ubuntu computer

[Donald F. Parsons MB.BS]

Hello!
I have two computers, one ubuntu and the other Windows XP. Both have 
separate ethernet connections to a Verizon FIOS modem. I can fire up 
both computers and then switch the video from one to the other using a 
Belkin Omni KVM switch.
When I have both computers running how can I transfer files from ubuntu 
to Windows or Windows to ubuntu?
Thanks
Donald Parsons
dfp10 at verizon.net