Hi there ,
I need to know more detailed technical information about the SIP protocol and how much it provides security ?
and I have read in the net but what I need is good tutorial if available , so please can you send links to tutorials u have tried and seen that it is good enough so that one can start from there

Thanks in advance

try this website below:

http://www.tech-invite.com/

there are a lot of of standards for SIP and IMS there.