As anticipated, Steve Jobs used the early part of today’s Macworld 2008 keynote to unveil a new movie rental service – through and updated version of iTunes – that will feature films from all major movie studios. The service will be available to iTunes users starting today, priced at $2.99 for older films, $3.99 for new releases, and $4.99 for HD releases, from a library that is set to include some 1,000 films by next month.

The rental titles will become available on iTunes 30 days after DVD release. Customers will have up to 30 days to start watching the film, and once a movie has been started, customers have 24 hours to either finish it, or watch it multiple times.

Additionally, the rental service goes hand in hand with a revamped version of the Apple TV also announced today. The original device was designed to allow customers to move video off the Internet from their PCs to their TVs, but the new Apple TV will not require a connection to a computer and will allow customers to rent movies and buy music directly from iTunes. The new device will sell for $229.