Apple has sent an email to all developers, requesting that all apps submitted now be made from, and for, the iPhone 3.0 software

The body of the email states:

"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."

So developers really need to get to work on making their apps 3.0 compatible, if they haven't already, since Apple will reject any app that isn't. The email seems to hint at the fact that apps for 2.2.1 will not be accepted until they are made 3.0 compatible. Does this mean that we won't see any updates for our current apps until 3.0 is out? It's uncertain.

So all iPhone users are expected to upgrade to 3.0 software when publicly available (but why wouldn't you) and iPod touch users will have to pay the $9.95 upgrade tax to get the upgraded software or be stuck with outdated apps and no access to new ones.