The code that 1629 released as part of the beta test reads and writes to files. The thread about it is here:
http://forums.usfirst.org/showthread.php?t=10274
Like Ryan said, it uses the standard file I/O VIs, so you can use any LabVIEW tutorial for file I/O to learn how you do it, and you can prototype it on your computer (very handy).
For the file path, use c:\ and it will put it on the root directory of the cRIO, which you can access by FTPing to the cRIO.