Apple apparently underestimated the resourcefulness of soon-to-be iPad owners because a few have managed to find what appear to be iPad versions of applications on the iTunes-based App Store.

It looks like many developers are adding “HD” to the names of their applications that have been optimized for the iPad, and PadGadget rooted out several that were appearing — at least temporarily — on the store Web site on Thursday. The apps they found included Ammoin HD, Azkend HD, Flight Control HD, Grind HD, HD Recovery, Labyrinth 2 HD, NBA Hotshot HD, Numba HD, Plants vs. Zombies HD, Sparkle HD and Worms HD.

Apple later pulled the references to the iPad versions of the apps.

The apps PadGadget found show there will be several games ready for the April 3rd iPad roll out, and assuming more developers can get their iPad apps submitted by the March 27 review deadline, even more will be ready to go on launch day.

Apple’s iPad is a tablet computer device that runs a version of the iPhone OS. It sports a 9.7-inch multitouch display, supports most iPhone apps, includes Bluetooth and Wi-Fi support, and some models offer 3G wireless data connectivity, too. The iPad is priced starting at US$499 for the 16GB Wi-Fi model.