Solving Linear Programming Models

Does anyone know of any resources (classes or otherwise) that could be used to solve linear programming models using PHP? This is similar to Solver in Excel.

Basically, I have a model where the user inputs their preferences and it generates a solution given certain constraints. There is the potential for just building this from scratch but I would like to avoid that if possible just because of the complexity of the whole thing and the existence of solvers (granted, I’ve only found ones for Excel).

I saw something on SourceForge about lpsolve(). Has anyone had any experience with this?

Also, I found a class called Simplex-In-PHP. Any experience?