2011 Theme – Create different sidebars

I’m running the basic 2011 version of WordPress on a site right now, and I need to use a different sidebar on one of the pages. Actually, for that page it’s the same sidebar information as the others, just with 4 added photos at the bottom of it.

I’m looking for the easiest way to create a different sidebar, whether it’s a plugin or editing the php files.

Can someone walk me through it?

Thanks!