Hewlett Packard is serving the Touchpad buyers a $50 rebate on the purchase of the new $599.99, 32GB TouchPad, but only Palm smartphone users can cash in.

Through July 31, you can get a $50 rebate on the purchase of a new 32GB TouchPad, writes HP's Jon Zilber on the Official HP Palm Blog. Proof of ownership of a Palm Pre, Pre Plus, Pixi, or Pixi Plus (initially in the US or Canada) will be required. This mail-in rebate is good wherever you buy your TouchPad, including preorders and reservations.

HP will release the two versions of the 9.7 inch TouchPad powered by webOS in the U.S. on Friday and in Canada in mid-July. The 16GB version of the tablet is priced at $499.99. Both the 16GB and 32GB versions will arrive in the U.K., Ireland, France, and Germany several days after HP's first media tablet makes its U.S. debut.

TouchPad with 3G connectivity via AT&T will be released later this summer.