I want to deploy a web caller. And for this, I will use Flash. But I have no idea how to communicate with my server to relay the call through asterisk.
Any help is much appreciated.
Opensource way do that - use red5 flash server or http://code.google.com/p/siprtmp/ project.
But i hihgly recomend you use already developed components, for example flashphoner.com if you are not expert in this field.