The Prince of Persia Epilogue expansion DLC (downloadable content) was released on February 26th, 2009. In case you missed it, here is a look at the story Epilogue which introduces a new area to the game known as The Underground Palace.
In addition the epilogue expansion adds a new spring attack for the prince as well as a new power for your partner Elika who has a new Energize move.
Give the downloadable content a look in this trailer.