Agentpress is a WordPRes theme, so yes.
Unless you are asking about can you use the theme on the *hosted* version at Wordpress.com, which is no. Because wordpress.com does not allow you to install your own themes.
These forums were CLOSED to new posts on November 19th, 2012. New forums are here: http://www.studiopress.com/forums/
and you will need to SIGN UP AGAIN.
If you need assitance with setting up your theme, go to http://my.studiopress.com/
and read the SETUP links or the TUTORIALS link on the side tab.
If you need Account Assistance
, file a help desk ticket at the same location.