More information would be helpful, but I'm guessing that you have XP on one partition and Windows 7 on another. If that's true, then you can move files from the XP partition to the Windows 7 partition just like you would copy back and forth between any two normal partitions.
Oh, ok. You can do this by setting the XP machine's folder that the contains the files you want to copy to be a "Shared folder". Then, on your Win7 computer, open up My Computer, expand the "Network" section (in the left hand column at the bottom), expand the [name of your XP computer] section, and the shared folder should be there. You can click it, and view and copy files to/from it.