you need to get the gallery2 source. the easiest way is:

cvs -d:pserver:anonymous@cvs.sf.net:/cvsroot/gallery co gallery2

Alternatively, visit http://gallery.sourceforge.net and download the lastest
stable release (minimum Alpha 4)


A few key Gallery2 installation tips:

# Be sure to include "User Albums" module when installing.
# Once installed, log in to gallery2 directly and click "Site Admin". Click the
  "User Albums" link and change "Create albums" to "When user is first created".
  Click "Save"
