Mac OS X Hints: Map Address Book addresses via Google Maps. This is the sort of low tech URL-based hack that is perfect for AppleScript, and very easy to debug.
An older Mac OS X Hints article discusses the plug-in capability and provides another sample script. From that, it looks like you capture the field to which you’re adding the contextual menu using an “on action property” handler; the title can be set with “on action title”; and the actual code is in the “on perform action” block.
Other address book plug-ins:
- iCal Scripts (Apple): schedule a call, create a “birthday event” (reminder), or create an event associated with the person
- Dates and SMS Scripts (Daniel Browne): send an SMS message via a Bluetooth phone, email, or AIM
- Skype call (bertlmike): open a Skype call
The plug-ins can also be written in Cocoa or Carbon.