Apple chief executive Steve Jobs said last night that outside developers will be allowed to create programmes for the iPhone.
Blocking outsiders from making programs that would run easily on the iPhone has been one of a series of restrictions that have annoyed users, even leading to some legal actions.
Mr Jobs, in comments on Apple's website, said a kit for developers will not be available until February, as the company works out how to open up the phone without exposing it to malicious programs.
"We think a few months of patience now will be rewarded by many years of great third party applications running on safe and reliable iPhones," Mr Jobs said.
Developers have tried to open up the iPhone for use in the United States on networks beyond Apple's US partner, AT&T, though Apple has blocked many such moves.
Apple said the company has not changed its policy on locking the phone to other networks.