For anyone using Asterisk, we have just recently published nAsterisk. This is a managed implementation of FastAGI that will allow you to interface with Asterisk from managed code. When time permits, we'll work on an AMI implementation.
You can download binaries and source code from Codeplex here.
Enjoy!
About Fabio
I was first introduced to software development at age 13. Today, I currently hold a Software Architect position at Teleperformance USA, where I primarily deal with emerging technologies, telephony, SOA, etc..