Yes, there is.
You have to use the REST API and specifically the "Signed Start" method. There is PHP and Python code for it at <
http://dev.karotz.com/api/signed.html>. The Python code works, don't know about the PHP. I've an implementation in Objective-C, but it's tied to Cocoa, so probably it's not better than Python for your scope (make me know if you want it, in any case).
The answer will be (when it works) around the lines of:
"<VoosMsg><id>c09ddf40-f08c-44e2-aa89-f102502e87f4</id><recipient>3c29cc7c91a2f98303fed6b316d4ec5f</recipient><interactiveMode><action>START</action><interactiveId>ae7f2f95-2b1b-48d8-882e-4628d6868db8</interactiveId><configId>3ebfd249-c8eb-4ced-b320-f681ad3aca82</configId><access>http</access><access>multimedia</access><access>tts</access><access>webcam</access></interactiveMode></VoosMsg>" so it can easily parsed also without any explicit XML framework.
Just keep in mind that you'll find that the API server is *really* unstable and without any error... if it don't like something, the proxy will answer you with a 501 Bad Gateway. Often, it will answer you with 501 in any case. :D Personally, I used the python code to test for the server availablity... if don't answer, then it's broken. I'm sorry but this is the state server-side.
Ah, there is a major drawback to not use a callback server: your session will timeout after ca. 15 minutes. I didn't find any way to keep it alive without using a callback server (that in my personal case I could not use, because I was writing an iOS app running on a phone). ;)
As a separate thought, I strongly think that the "old" nabaztag APIs were *way* better (and much more stable) but, you know, that's the progress. ;)
Good Luck!
Ciao,
gt