They list 4 different sizes on their web site, although at the moment all are out of stock with expected time of arrival of 11/30/09 for the two larger models. The 8 by 6 inch model has 14 user reviews on Monoprice.com with a very high satisfaction rating. The tablet comes with 2 pens and extra nibs for the pens. Driver software is included for both Mac and Windows.
I have had both good and bad experiences with budget-brand graphics tablets, but the Monoprice name and Jacci's recommendation gives me some confidence that these could be a good low-cost alternative to a Wacom tablet. If you've used a Monoprice graphics tablet, please share your experience in the comments.