WASHINGTON (AP) - When Barack Obama announces his choice for vice president, the real payoff may come during the next few months - one text message at a time.

Obama's campaign plans to break the news of the Democratic candidate's vice presidential pick to people who have signed up to receive e-mails and text messages from the campaign. It should give Obama's team access to tens of thousands of cell phone numbers that could be used to mobilize voters under 30 on Election Day.

Obama's electronic outreach is the most prominent example of a larger movement by members of Congress and political campaigns to present their message and connect with voters through text messaging on cell phones, social networks such as MySpace and Facebook, and the microblogging site Twitter.