The official OpenAutonomy server reference implementation.
NOTE: The full "server" is not required to interact with OpenAutonomy.
The main implementation priority is ubiquitousness. To that effect, the server is implemented in PHP with few external dependencies to ensure that this can be run on even the leanest of web hosts.
The project includes the related tools from FreeMarker templates (used to generate RPC glue code) to the PHP "compiler" (static inlining of PHP includes in order to reduce runtime search overhead).
MP-Suite is a client/server script that enables remote MySQL through an XML-RPC interface. This way, you can remotely access databases that are not remote-access enabled.
Infra-Red is a package of scripts designed to set up a service oriented architecture in PHP. It includes the server with an example service, a client library for the codeigniter framework and a stand alone client library.
A simple, easy to use RPC alternative to SOAP or XML-RPC with built in code generation. Focussed on ease of use, simplicity, and having a human readable protocol. Check out the WIKI for documentation and examples.
Aura is a plug-and-play XML-RPC application framework in PHP5. It bundles an XML-RPC client and an XML-RPC server. It has simple and clean API and allows exposing already written functions and classes as web services for instant productivity.
The PRAjax class can be used to reflect PHP code into JavaScript and Ajax methods and vice-versa. PHP objects can be used in JavaScript trough Ajax calls, both properties and (registered) functions.
PHP-O-Lait is a library that, in 2 boiler-plate lines of code, allows you to call server-side PHP code from client-side JavaScript. It's so easy, in fact, that you don't need to know how it does it (hint, it uses Ajax and JSON).