I will like for you to take a look at the [login to view URL] android application. As i want exactly the things. With the addition of callback as an option to call. so we will use open source voip sip application for wifi and 3g calling, and use callback url for call back, and auto dialing of access number and destination number for the direct dial.
There is an application on android also called calling card pal. That will give you an idea of the direct dial features.
I will be sending you more details on this. But start taking a look at the options i have shown above.
Give me your bid.
Regards