An email has been sent out to developers telling them Apple is now accepting application submissions for the iPad App Store — a special category of the existing iTunes App Store for iPhone and iPod touch. 9to5Mac has the text:

iPad will begin shipping soon and your opportunity to be part of the grand opening of the iPad App Store starts today. Submit your iPad app now for an initial review by the App Review Team and receive feedback on its readiness for the grand opening. Submit Your App by March 27.

• Build and test your iPad app using iPhone SDK 3.2 beta 5 available on the iPhone Dev Center. Only iPad apps built with iPhone SDK 3.2 beta 5 will be accepted for this initial review.

• Upload your distribution signed app through iTunes Connect by Saturday, March 27, 5pm PDT.

• The App Review Team will review your app on iPad and email you details about the readiness of your app.

• You will also receive additional information about submitting your app for final review before iPad ships.

• Only apps submitted for the initial review will be considered for the grand opening of the iPad App Store.

As TUAW points out, however, there’s some risk involved:

the simulator uses many Macintosh frameworks and libraries, offering features that are not actually present on the iPhone. Applications that appear to be completely operational and fully debugged on the simulator may flake out or crash on the device itself. You simply cannot fully debug any program solely by using the simulator and be assured that the software will run bug-free on the iPhone. Here at TUAW central, we’re assuming (or at least hoping) that Apple will be testing device builds on real devices.

+1 to that. It would no doubt annoy users not to have iPad-specific apps available on April 3. I would annoy them more if those apps crash due to never being tested on, you know, the actual iPad hardware they’re supposed to run on…

Maybe this explains, at least in part, the new iPhone 3.0 Beta 5released yesterday? Looks like Apple is super-eager to get developers testing and submitting 3.0 compatible applications.

We’re really eager to see what developers are coming up with to leverage all those great 3.0 features as well. Really, really eager. Ahem.

Full text of Apple’s email to developers:

All apps must be compatible with iPhone OS 3.0

Millions of iPhone and iPod touch customers will move to iPhone OS 3.0 this summer. Beginning today, all submissions to the App Store will be reviewed on the latest beta of iPhone OS 3.0. If your app submission is not compatible with iPhone OS 3.0, it will not be approved.

Existing apps in the App Store should already run on iPhone OS 3.0 without modification, but you should test your existing apps with iPhone OS 3.0 to ensure there are no compatibility issues. After iPhone OS 3.0 becomes available to customers, any app that is incompatible with iPhone OS 3.0 may be removed from the App Store.

Begin testing now

iPhone OS 3.0 beta 5 and iPhone SDK 3.0 beta 5 are now posted to the iPhone Dev Center. Start testing today to ensure your application runs on iPhone OS 3.0. Visit the iPhone Dev Center for additional development information including iPhone SDK Release Notes for iPhone OS 3.0 beta 5 and Getting ready for iPhone OS 3.0.

(Thanks DevX for the tip!)