Mark Stevenson gave a great demo at our September Multimedia SIGi meeting about how iTunes can support more than one iTunes Music Folder. Well -- that same trick works in iPhoto v6 too! 
Pressing the Option key as you launch iPhoto will allow you to Choose which of your existing libraries it should use. You can also Create a new Library.
I've written a more complete article on the subject on my own website here
if folks want all the detailed steps.
Thanks again to Mark for showing us that trick in iTunes and I simply thought it would be neat try it in iPhoto and to no great surprise it worked the same way
Now we just need to hope and wait for Apple to move that feature to someplace more obvious in the user interface.