Yes, LOCOG is planning on having ticket booths set up around town selling tickets. The are loading a few new tickets onto their site daily, it pays to check often.
For those with access to Twitter, @volshy has the best information. It does appear as though CoSport USA will likely not obtain any more tickets, outside of football.
Be very wary of purchasing tickets from other than official outlets. Visa has already flexed it's muscle with some US ticket brokers.