Sharp Serialization Library serializes and deserializes primitives, ArrayLists and Hashtables, compatible with PHP serialize(). Use it for SOAP/Web Services communications where Hashtables cannot be passed otherwise, or saving to a file readable by php.
It perfectly works even in the Mono environment! Just don't forget to change the project type;)
I use this library instead of JSON.NET lib. I found it easier to use even in CFNET. I just found a small bug when unserializing accent characters that I have patched and sent to author.
Best solution for comunication to PHP API