Hi Pujari, It's great that you want to contribute. I think the first step would be to check out the Gears code from http://code.google.com/p/gears/source/checkout. Instructions for how to build are at http://code.google.com/p/gears/w/list.
As for code reviews, as you've seen, all reviews take place on this list. However, most of the code reviews taking place at the moment are updates and fixes to existing pieces of Gears code. These require quite a bit of background and context to understand properly, so they might not be the best place for a newcomer. I would recommend that you take a look at the issue tracker at http://code.google.com/p/gears/issues/list. Pick an issue that you think you can fix, and submit a patch for review to the mailing list. It's probably sensible to focus your efforts on a particular module and/or platform. Numerous modules have design docs at http://code.google.com/p/gears/w/list, which would be useful to read. Steve
