Or are you thinking of using samba so you can use file and print sharing ?
What you can do with out any prob's is read the files in the windows partition. Though if you have windows XP, formated as NTFS then support is a little sketchy, but I understand that you can write to the partition if you've got things set up correctly. If your windows partition is set up as FAT32, then you should be able to read and write to the windows partition.
As far as running windows app's it's either wine/winex or crossover office/plugin. There's win4lin which cost's or if you are into this seriously then there's VMware which is a system emulator, and you can actually have windows and linux running simaltaneaously (but it's expensive).