There is a cheaper way.. it works and does not void warranty.
Check it here : XSIM V4 NO CUT - Unlock any phone easy - 1 UNIT on eBay (end time 07-Jun-10 03:50:11 BST)
I really don't think that there is a cheaper way fro that.. (do note that the shipping is also free.. sweet!!!
By the way.. i have tested it myself and it does work nicely!!
(Took about 3 days to get to me.. that's fast!)