The BBC previously said iPlayer was scheduled to launch in the autumn, but Ashley Highfield, the corporation's director of future media and technology, said today the free catch-up service will launch on July 27.
The service will enable users to download programmes from the BBC's archive of TV and radio programmes, with 30 days in which to watch the programme file. Once watched, the programme file clears by deleting itself.
Highfield said the corporation was aiming to attract 1m users to its iPlayer service within the first year.
The BBC said it was is in discussions with a wide range of potential distribution partners, including MSN, telegraph.co.uk, AOL, Tiscali, Yahoo!, MySpace, Blinkx and Bebo.
The BBC already has a deal in place with YouTube, which will carry links to iPlayer. The corporation is also in talks with Virgin Media about a cable launch later this year.
Highfield said: "We are committed to making it as easy as possible to use BBC iPlayer. Developing a version for Apple Macs and Microsoft Vista is absolutely on our critical path.
"Our vision is for BBC iPlayer to become a universal service available not just over the internet, but also on cable and other TV platforms, and eventually on mobiles and smart handheld devices."
The technology behind iPlayer has been created and developed by the BBC's Future Media and Technology division, in partnership with Siemens and Red Bee Media. The BBC first began working on the iPlayer project three years ago.