The webOSroundup site recently reported that HP sent out a second news e-mail (er, I never got either!) that contained promo codes for 4 more apps: Flashcards, Beyond Ynth HD, iCookbook and Supersonic HD.
Sadly, these codes were yet again limited to quite a small number, so I missed out on all of them - it didn't help that I never got the latest e-mail. By reading comments on that article, I eventually sussed that UK users can indeed sign up to what's called a "Palm newsletter". You should use your TouchPad e-mail address in the login box on the right-hand side first to log in, otherwise it'll reject the form submission.
Don't forget to tick the "Palm News" box (I gave a fake mobile number - what on earth do they need that for - my TouchPad has no 3G - I guess it's for Palm phones) and then click on Submit. Hopefully, the 3rd e-mail will actually come through for me - it's quite frustrating that you get minutes to claim the code because although they give an expiry time of weeks for the code, there's only a small number of them.