The Cameroon international completed his move to the Nou Camp yesterday.
Song explained his decision to leave the Gunners, describing the chance to join the Catalan giants as a "once in a lifetime opportunity".
"I am very happy to be at Barcelona, to be a Barca player," said the 24-year-old. "It is a big day for me and my family. I said yes to Barca because this is a once in a lifetime opportunity.
"[Cesc Fabregas] has told me many things about Barca, but he did not need to convince me. I know all about them, I have seen them on the television. When you move to a new place you have to adapt and Cesc will help me. The style of play is similar to Arsenal.
"I will try to do my best. We will aim to win trophies because this a team of champions."
Song also clarified that he has no problems with Arsene Wenger, despite reports suggesting that he was sold because of a poor professional attitude.
"I want to thank Arsenal and Arsene Wenger for letting me come here," he added. "I wanted to make the move and I am happy to have taken this decision. I have no problems with Wenger."
The central midfielder joined Arsenal from Bastia in 2005.