Obama picks Biden for veep

CHICAGO, Illinois (CNN) - Sen. Barack Obama has selected Sen. Joe Biden of Delaware as his running mate on the Democratic ticket for the White House, two Democratic sources told CNN.

Confirmation that Obama chose Biden, a veteran U.S. senator who twiced failed in bids for president, came after word that three other Democrats who had been considered frontrunners to be Obama's running mate had been told they're no longer in the running.

The Obama campaign says it plans to announce his vice presidential running mate in a text message Saturday morning - in advance of an afternoon rally in Springfield, Illinois, at which he is expected to appear with his VP candidate.