Protecting PHP Source

[LucaUWF]

I develope applications for a close knit community of internet users. Up till now I have developed everything for them for free (I'm nice like that ).

But now I want to try and get a little return for my time and effort as most developers do. The problem is, so close knit are those I develope for that I know without a doubt that should I create some php script for them that it will be passed on over the net like wildfire, destroying my chances.

My question is simply, is there any way in which we can protect php code?

Doing a search there appears to be some encrypting apps, but I don't fully comprehend how they work. Obviously they encrypt the source, but in order to decrypt it, would the client server have to have the decrypt key/code, and in which case, wouldn't that defeat the object of encrypting it in the first place, since the decryption socket can be passed along with the scripts?

Any help, advise, info is grately appreciated.

TIA