If you are talking about the spiral bound notebook - 6.5" x 8.75".
If nothing else, the dimensions are listed an the product create pages.
These two links are the fastest ways to find the products that I know of, if they are newer items and have no guide files. The sell/all page isn't quite as current at the moment as the first link (I don't see the very latest items, like clocks, playing cards, dart boards, yard signs) but it is organized alphabetically, which is super nice.
http://www.zazzle.com/createhttp://www.zazzle.com/sell/allI miss the guide files for everything new.
I personally have loved them and the fact that they take the guesswork out of everything. We who relied on Zazzle's versions of them gratis each new product were so spoiled, lol :-)