Apple just announced to developers that it's now accepting iPad applications. From the sound of it, applications submitted now will have a shot at being reviewed and approved before the iPad launch next month, though since most all apps developed so far have only been tested in the emulator, this is more of a "feedback" round for devs looking to be ready for the launch without actually testing their apps on hardware themselves. Apple says that "[o]nly apps submitted for the initial review will be considered for the grand opening of the iPad App Store," so you probably shouldn't wait around -- unless you've got one of those iPad test units headed your way, or you're a hardware-testing purist that will wait for the iPad launch to start testing apps and miss one of those cushy spots on the opening day iPad App Store. Either way, we can't really imagine we'll be seeing true 3rd party iPad app greatness until a month or so after the launch, but who are we to talk down a "gold rush"?
Update: We just saw that the deadline for getting apps in for the first round is March 27 at 5PM PT. Fire up that SDK 3.2 beta 5 and start cracking!