And lots of them are games...
Mobile analytics firm Flurry says it's already tracking more than 200 apps being used by 50 tablet devices on Apple's Cupertino campus.
The company has been able to measure the activity because its technology is being used to provide analytics for the apps.
"Because Flurry could reliably "place" these devices geographically on Apple's Cupertino campus, we have a fair level of confidence that we are observing a group of pre-release tablets in testing," blogs the company.
"Testing of this device increased dramatically in January, with observed signs of life as early as October of last year."
So what have they learned? More than 150 of the apps downloaded and launched by the tracked users were games, while Entertainment and News & Books both had more than 60. This presumably includes duplicates, judging by Flurry's headline 200 figure.
"With a larger screen, more memory, multi-touch and multi-tasking expected, games will play better than ever on Apple handheld devices," says Flurry.
"The mix of applications observed comprises mainly of media and entertainment consumption as opposed to enterprise, productivity and computing."
Flurry says the tablets that it tracked were NOT running iPhone OS 4.0, but rather 3.2 - which has not yet been released for iPhone. The company says it's satisfied that the devices it's tracking are not merely iPhones running the new OS, though.