Well, if you want to read a file in windows from your linux partition, you could (assuming you have an ext2 or ext3 file system) use the windows ext2 driver from
http://sf.net/projects/ext2fsd (read the FAQ first- it's in the docs section). If you like that driver you may also be interested in a driver which lets you use your Linux swap partition for Windows swap space-
http://insidewindows.info.
The easiest way to transfer files between Windows NT/2K/XP and Linux, however, is to have a FAT partition on your harddisk.