Hello, i have tried this before the easy way - (simple setup). i made a tutorial a long time a go and it's way to old and won't work anymore, thats why i decided too be Mr Nice Guy, and start to work up some sort of a tutorial or at least something to help you start, i don't know if i will go in depth but i will try to cover it so you at least know more then you did 5 Min's ago ;) so here we go,
What you must first know is some basic stuff, SIP,
A SIP server is only a part of the whole requirement. A SIP server is just a registrar which keeps track of which phones are logged in and available and manages signaling between them.
for this you can use,
SIP PHP CLASS
useful sip info and code.
SIP Server
Voip server
then you need a sip webphone/web-softphone
this is the interface part on your web,
this can be made with ajax/jquery or flash etc.
You could do it with some basic html/javascript.
This is a webphone/softphone for the web. you just add your sip server details and what not you have a basic system now but your a long way from a perfect setup.
Some links you should check out:
http://stackoverflow.com/questions/1...text-to-speech
http://www.voip-info.org/wiki/view/Asterisk+PHP
http://www.voip-info.org
http://stackoverflow.com/questions/3...ip-on-php-site
http://www.phpclasses.org/package/65...-instance.html
http://www.eukhost.com/voip-dedicated-servers.php
http://www.google.com/webhp?hl=sv#hl...ae79bbfd161197
http://www.bablotech.com/2009/04/12/...rver-for-free/
http://www.asterisk.org/
http://www.google.com/#hl=sv&biw=192...ae79bbfd161197
http://www.mizu-voip.com/
http://www.mizu-voip.com/Products/WebPhone.aspx
http://www.google.com/webhp?hl=sv#hl...ae79bbfd161197
http://level7systems.co.uk/en/blog/C...l+with+PHP-SIP
http://leifmadsen.wordpress.com/2011...r-in-sip-conf/
http://www.freepbx.org/forum/freepbx...answers-a-call
http://www.google.com/#hl=sv&source=...ae79bbfd161197
http://www.voipuser.org/forum_topic_13705.html
http://www.google.com/#hl=sv&biw=192...ae79bbfd161197
http://www.voip-info.org/wiki/view/w...ftphone+Doddle
http://kb.super-phone.com/tiki-index...ia+Super-Phone
http://www.google.com/index.php?page...ae79bbfd161197
http://www.xenialab.com/en/
http://www.voip-info.org/wiki/view/O...+VOIP+Software
http://www.howtoforge.com/asterisk_pbx_linux
i will add more & edit and what not,
but this will do for now hope it helps you
get on the right path at least.