With most rebates, filling them out online gives you easier tracking *, you still have to mail in the UPC (or a copy; see instructions), receipt.
I prefer online submissions, because I can check if they have received
my forms etc. without having to call and wait on hold etc.
* In some cases you won't get tracking at all if you don't fill them out online, in other cases they will e-mail you a tracking number, but that won't be till AFTER they receive your paperwork; this is why I prefer online submissions
Plextor PX-716A TLA0304
Plextor PX-716A same TLA
LiteOn 52246S 52X CD-RW
LiteOn 52246S (another)
LiteOn 52327S 52X CD-RW
TDK 40X USB 2.0 CD-RW
TEAC CD-W540E 40X CD-RW