[Asterisk-biz] Offering International Calls via Asterisk

[fruit f*cker 2000]

Hello,

I'm located in Singapore and I'd like to offer International calls.
I'm new to Asterisk and I can't seem to find the answer to this.

Is it possible for me to have an E1/T1 connected to a Digium card  to
a server running Asterisk, and have calls connect to either Nufone,
Teliax, BroadVoice, etc. And even use the best VoIP provider based on
destination rate of the call.

I've also ran into this link about prepaid call cards:
http://www.voip-info.org/wiki-Asterisk+Prepaid+Applications

Is it possible to use all of this for this kinds of business model?

Best regards...