Blockbuster is on the verge of declaring bankruptcy under the weight of competition from Internet services, sources said late Thursday. Attendees of a top-level meeting told the LA Times that Blockbuster was warning major movie studios of a "pre-planned" Chapter 11 bankruptcy likely for mid-September. The move would give it a chance to reorganize, offloading at least some of its $920 million in debt and letting it out of lease requirements for at least 500 failing stores.