I have an iMac & have thousands of photos in the iPhoto app. For reasons I won't get into now, I have two iPhoto libraries on my HDD & I don't know how to quickly access both. I believe I use the option key plus something else. What else? I have an iOmega HDD 1H4 and using OSX
Computers & Internet - Iomega - HDD External Desktop (32660) 80 GB Hard Drive
Answers & Comments
Have a look here Fat Cat Software - Home they do software to manage multiple libraries.
I'm told it works very well.