If you're still looking for a Hearthstone beta key, you may find your luck lies with the official Hearthstone Facebook page beta key sweepstakes. Follow Hearthstone on Facebook, fill out the form, and enter for your chance to win. There will be two drawings of 500 winners each, one on August 27th and one on September 3rd. That's a grand total of 1,000 winners from this particular giveaway -- not too shabby!
So click that link and throw your metaphorical hat in the ring; and good luck! We hope to run into you in the beta!