Bestbuy sometimes has them in stock but I got mine from Newegg when they first came out.
The keyboard just absolutely rocks. All my posts on this forum are on the TF. (Transformer model TF101) I can type just as fast as a regular laptop. Plus the buttons on top are perfect for music playback, the touchpad good for scrolling.. Also you don't need a case to hold it up. My dad and I were video chatting and he had to keep fixing his Galaxy tab because it wouldn't stay at the right angle. Mine is just put it on whatever surface and forget about it..