[Asterisk-Users] Tie web application to VOIP

[K J]

I want to tie my web application (built using .NET + MS SQL Server)
into a VOIP service so that users can call each other.  I want them to
interface with my application's username system.

On the receiving user's end, he can either receive the call using a
VOIP phone, or windows application (like skype).

I would use Skype's API, but it appears I need to use their username
system, and not my own.

My question is, what software/hardware solutions would I need to do
this?  Any suggestions/feedback would be greatly appreciated.

Btw, I was told that Asterisk + SER would do the trick.  However, I'm
a newbie to the world of VOIP.  If someone can give me some
tips/hints, it would be great.