PHP product licensing...

I'll get right to the point, then explain after... I'm looking to release some PHP code as partially open-source. Basically a GPL-like license for non-commercial use, and proprietary license for anyone else. I'm wondering about people's experience with various licenses (open-source or not). I'd be really glad to hear opinions and experiences about any successes and failures. As for my reasoning: As I understand it (correct me if I'm wrong), the GPL leaves some holes with regards to code used internally within a company (especially web stuff) where GPL'd PHP code can be used and changed internally by that company without returning changes even if the code is used in a public-facing website - so long as they don't re-distribute the software. I've read through a bunch of other licenses, but I'm no lawyer. So rather than jumping blindly, I thought I'd seek out the opinions of those who've been there. There's no substitute for the concrete experience. :-) I really like the idea of open-source software, so I would very much like to release my code so that it can benefit the open-source community, but make sure that commercial use is appropriately controlled at the same time. Please reply to the list only, no need to cc. Cheers, jon