restrict live application, how to? not to restrict users but the publishers
So there are several things that you can do using Server side actionscript.
1) You can restrict the number of publishers. You can keep a count of number of publishers via the application.onPublish() function and disconnect users after a particular count is reached. See more about the application class here : http://help.adobe.com/en_US/FlashMediaServer/3.5_SS_ASD/WS5b3ccc516d4f bf351e63e3d11a11afc95e-7edf.html
2) You can restrict publishers based on the type of client using the clientObj.agent property. See more about the client class here : http://livedocs.adobe.com/flashmediaserver/3.0/hpdocs/help.html?conten t=00000258.html
3) You can use combinations of these.
Hope this helps.