Home network w/ XP pro desktop and Vist Home pro...

Question

I bought a new laptop w/ Vista Home Pro and hooked it up thru a wireless network with my Desktop computer running XP pro. Both run fine separately but I would like to access my home computer desktop with my remote laptop. The Desktop computer is hooked to the Linksys wireless G by hardwire and the laptop is wireless. I don't want to load redundant software on the smaller (160 gig) Toshiba HD and the desktop computer too. Can I access the desktop computer software by laptop? If so, How? Thank you