It appears that not anyone can sign up and become a registered developer for the iPhone. Apple is sending out rejection letters via e-mail. Twitterers are firing up their tweets in protest and anger.According to The Unofficial Apple Weblog, people interested in developing for the iPhone are being rejected by the thousands.

Erica Sadun writes, "If you've applied for Apple's iPhone Developer program, check e-mail for your rejection letter. The twitterati are reporting widespread disappointment and anger as thousands of iPhone developer hopefuls have received a 'Thank you but no thank you' message in their in-box. The e-mails are arriving with the subject of 'iPhone Developer Program Enrollment Status'."

Have any of you received such notice? A number people have responded to Sadun's piece with comments. More than a few were among those rejected by Apple.

One commenter said, "Denied! That sucks!!! What is or was the criteria? Since the application did not ask you anything important like what are you planning on working on... Are people who are getting accepted top-level ADC members?"

So what does it take, Steve? Do you need to be an official company to develop applications for the iPhone? Do you need to already be an ADC member? Can individuals apply? What are the criteria which you are using to judge these developers? Are you too worried about hackers?

It might be fair to make those criteria public so people who won't qualify don't register in the first place. After all, over 100,000 people have downloaded the SDK.

As my colleague Mitch Wagner pointed out earlier this week, the SDK could indeed be the iPhone's Achilles' heel. The negative press generated by rejecting developers will only further tarnish Apple's image and anger developers even more than they already are.

Update:

Erica Sadun collected some more information about the rejections. She said:

So it appears companies aren't immune to being rejected. I ask again, Apple, what are the criteria you are judging by?