There is a jail breaker's "store" called Cydia, which is an App Store for the tweaker. However, that's the only other place to get apps and tweaks (other than the App Store). Jail breaking does not mean there is another place to get apps for the iPad - you still have to get them (whether free or paid) from the App Store.
Any other means of getting apps for the iPad would be via piracy, which is neither condoned or supported here at iPadForums (cause it's against our rules ... and illegal).