From theonering.net:

Warner Bros. today announced what has been suspected and rumored: the studio is bringing “The Hobbit,” to the San Diego Comic-Con in a big way. Most surprising is just how big as director Peter Jackson, producer and co-screenwriter Phillipa Boyens, actor and director Andy Serkis along with featured actors Martin Freeman, Ian McKellen and Richard Armitage are all expected at the Saturday, July 14 Comic-Con panel in Hall H hosted by Warner Bros.

Read more over at theonering.net. Exact panel timings are expected to be published shortly.

UPDATE:

Timings have now been revealed for The Hobbit panel. It forms the third and final part of the Warner Bros presentation in Hall H on Saturday July 14, beginning at 14:30PDT and scheduled to finish at 17:00PDT. The Hobbit panel follows the panels for Guillermo del Toro’s ‘Pacific Rim’ and the new Superman film ‘The Man of Steel’, so to see The Hobbit panel, you have to attend the entire Warners Bros panel. Due to the ‘world’s first premiere footage’ from all three films, this is widely expected to be one of the most popular panels of the entire four days of Comic Con - be there early for a chance to get in!