The question says it all: I'm looking for working, open source, implementations of algorithms (or derivatives there of) initially described in the Boids paper.
It looks like most of the code out there was written before "Open Source" really meant anything. I asked Mr Google:
You're unlikely to find anything specifically "for the iOS" (or even written in Objective-C), but C and C++ versions should be easy to port. .NET versions should be easy enough to run using MonoTouch.