Currently, no released integration between coppermine or geeklog exists.
I am however working on it, and have a beta version of a Geeklog 1.3.12 (CVS Version!) to Coppermine 1.4.1 (BETA) bridging file.
However, you should note that using geeklog 1.3.12 CVS in production is strongly discouraged, as is using Coppermine 1.4.1 Beta. They are not yet released to the general public.
My bridge should work fine with Geeklog 1.3.11 but is only tested on 1.3.12. It will not work with coppermine 1.3.x.
You can find it on the thread over at the coppermine forums here:
http://coppermine.sourceforge.net/board/index.php?topic=19304.0
Attached to the last post I made:
http://coppermine.sourceforge.net/board/index.php?topic=19304.msg89820#msg89820