Barack Obama has named the man he wants to be America's next vice president by texting his supporters.
Obama is hoping to be picked as the man to take over from George Bush as the next US president when an election is held in America in November.
But first, he had to to pick a deputy and decided to text people to tell them he'd chosen a man called Joe Biden.
In the election, Obama will have to beat another candidate, John McCain, to get President Bush's job.
There are two main political parties in America - the Democrats and the Republicans.
Before an election, each party picks the person they want to be the next president, and each candidate chooses their own vice-president.
Then the two candidates travel across America trying to win enough votes to be named president.
Obama is the person the Democratic party has chosen, while McCain is the Republican choice. President Bush is also a member of the Republican party.
The countdown to the November election really kicks off on Monday, when the Democrats hold a huge gathering - called a convention - in Denver.
That's also when Mr McCain is expected to name the person he wants to be his vice president if he wins the November election.