Apple announced they will open up the iPhone for 3rd party developers but unfortunately it will still take a couple of months until the SDK will be released.
It will take until February to release an SDK because we’re trying to do two diametrically opposed things at once—provide an advanced and open platform to developers while at the same time protect iPhone users from viruses, malware, privacy attacks, etc. This is no easy task. Some claim that viruses and malware are not a problem on mobile phones—this is simply not true. There have been serious viruses on other mobile phones already, including some that silently spread from phone to phone over the cell network. As our phones become more powerful, these malicious programs will become more dangerous. And since the iPhone is the most advanced phone ever, it will be a highly visible target.
Some companies are already taking action. Nokia, for example, is not allowing any applications to be loaded onto some of their newest phones unless they have a digital signature that can be traced back to a known developer. While this makes such a phone less than “totally open,” we believe it is a step in the right direction. We are working on an advanced system which will offer developers broad access to natively program the iPhone’s amazing software platform while at the same time protecting users from malicious programs.