You could have downloaded ABMenu 3.0b4 for Mac from our application library for free. This free Mac app was originally produced by David Blyth. The software lies within Productivity Tools, more precisely Mind-mapping.
From the developer:
ABMenu helps you get to the contact information stored in your address book on Mac OS 10.5 and above easily and quickly through a convenient menu item in the upper right-hand corner of your screen.
Features:
Semi-transparent address book "cards" that allow you to see contact information without disrupting your work flow
Right-click or hit return to act on the data -- compose a new email, map an address, send an IM!
You may want to check out more software for Mac, such as EntourageABMenu, which might be similar to ABMenu.