Hewlett-Packard Co. said Monday it cut about half its information-technology operating costs and implemented other changes that will equate to savings of about $1 billion per year. Palo Alto-based HP (NYSE:HPQ) said it ended a revamp of its IT operations that emcompassed about three years and will also mean a cut in internal IT spending to about 2 percent of revenue in 2009. In 2005 the company spent about 4 percent of its revenue in that area.HP said it consolidated more than 85 IT data centers into six centers and cut energy consumption by 60 percent, partly because of a 40 percent decrease in the number of servers.The company also cut about 10 percent of its work force when it began the restructuring process.