AOL says it plans to cut about a third of its work force once it is spun off from Time Warner. That would amount to nearly 2,300 of the roughly 6,900 workers at the struggling company. AOL said in a securities filing today it will impose the cuts on a voluntary and involuntary basis. The company hopes the move will trim annual costs by about $300 million. Time Warner said this week that it will spin AOL off to investors Dec. 9.