I want to tap into the "Find My Friends" feature of iOS (5.x and/or prior) but am not locating any API to support this feature for developers. Does anyone know if/where the hooks for functionality can be found in the docs?
I'm not sure if you're asking for an API to directly tap into the Find My Friends functionality or if you're asking for something similar to it, but Find My Friends is an application, not an API, and Apple does not provide any API's or libraries to integrate one's app with Find My Friends. I'm sure you could implement your own Find My Friends type app with the Core Location framework.
You can check out the Location Awareness Programming Guide too to find out how to get the user's location, getting direction-related events, etc.
There is also a LinkedIn discussion titled "How to make an app simliar to Apple's Find My Friends" that contains some useful information in how you would go about implementing something similar to the Find My Friends functionality.
Hope this helps!