Apple Prepares to Unveil iPad 2 (AAPL, RIMM)

Apple

is preparing to unveil its new iPad 2 today in San Francisco, at the same time that most competitors are releasing their first iterations of tablet computers. On the eve of the unveiling, Blackberry

invited a select number of journalists to preview its new Blackberry Playbook tablet computer. The new tablet comes on the heels of an enormously successful first generation iPad that sold more than 15 million units and accounts for 15 percent of Apple's revenue. While Apple, the world's most valuable technology company with a market cap of $321 billion, traded slightly down yesterday, Apple's stock soared 10 percent last year upon release of the first generation iPad, as reported in the

. The new model is expected to be lighter, thinner, and faster than the previous model. It is unclear if Apple CEO Steve Jobs will be present at the announcement.