Chimp Studios (http://glp.chimpstudios.com/) has introduced Guest List Planner 1.0 for Mac OS X (10.5 and higher). It’s available for US$14.99 at the Mac App Store.
Guest List Planner is an event planner app featuring one-click import of complete lists of names and addresses stored in the user’s Address Book, Gmail and Facebook accounts. With all contacts imported, you can drag selected names onto the Guest List. Once a tentative Guest List has been created the app allows the creation of categories, such as Groom’s Side and Bride’s Side, etc. The app also imports and exports .csv files to and from spreadsheet applications.
The app allows the event planner to import large contact lists without searching all the different places on their computer their contacts may be stored. From a single small toolbar, the user just clicks on the icon for Address Book, Google Mail, or Facebook, and hundreds of names appear in the People Column, located on the far left of the screen.