VOIP

Hello Sir,
My name is Eklavya Jain I am a Software Developer.
I just have 6 Months of experience on ASP,VB,XML and JAVA.
The Company that I will be Joining is into Telecommunication.
that means I will have to work on VOIP , IVR.
I need Guidencehow should I begin .
Could U Guide me.
And a few Sample Codes.
Thanking You
Regards
Eklavya Jain