There isn't much on the site itself besides a link to download the beta. You can find out more on the Continuity Keypad Twitter account, including plans for the Mac App Store and updates to the beta. Right now those plans include ending up in the Mac App Store at 99 cents, and a steady stream of updates like adding redial and a Notification Center extension.
If this all seems far too boring, you can always make calls from your computer in geekier ways.