when we developed SmartInspect 1.0 we actually thought about building a PHP library and already wrote some code for it. We later decided to focus on .NET, Java and Delphi so the PHP code was never released (nor finished).
It would be quite easy to build a simple PHP SmartInspect library, but as we don't plan to release or develop one, you could give it a try yourself if you have a need for it.
The format and protocols are documented here:
If you are going to develop a SmartInspect compatible logging library for PHP, please contact me and I will give you some tips/hints (click my name below to send me an email).