What is WPG2?
WPG2 is a WordPress Plug-in that embeds Gallery2 within WordPress to share photos, videos and any other Gallery2 content seamlessly into the WordPress Sidebar and Blog entries. The current version of WPG2 is 1.0, released on September 13th, 2005.
Good example of Gallery 2 integration into WordPress – http://www.ozgreg.com/
Gallery 2 Download – http://codex.gallery2.org/index.php/Gallery2:Download