[asterisk-users] inbound call voip providers

[srgqwerty]

Hello:

I want to have a local telephone number that, when the people calls this 
number (via mobile or normal PSTN), the voip provider stablishes a SIP 
session to my asterisk box.

It is possible?

If yes...
What providers have this service in Europe?
It is difficult to configure and get things working ok?
Will my asterisk box see the mobile or normal PSTN phone# that is calling the 
number  (callerID)?
Who many SIMULTANEOUS sessions (calls) can be active in this scenario?
It is possible to have multiple asterisk boxes and tell it to the voip 
provider in order to "balancing" the asterisks?
Can my asterisk box have IVR support under this scenario?

Thanks a lot.

Regards