Multi-threaded port listener

Anyone find any good tutorials, code samples, etc. on such a thing? Basically, I want to write server (in PHP) that listeners on a particular port, and spins off a thread/process (essentially, execute a separate script) for each incoming connection. There won't be a lot of data to process, but there will be many simultaneous connections—upwards of 1000s of connections (each spun off as seperate threads). ...Rene