Asterisk conference call people in

I am have a problem in the company i am working for. and i think that asterisk can help me. we have a asterisk conference that all the sales people are using in the mornings meetings.
But some of the sales people don´t have money to call the conference number on the phones.
can i get Asterisk do call the numbers, and read a message like. hello. press 1 to enter conference call. and when the press 1 the shod be connecter to a conference in the asterisk pbx?

Yes you can have asterisk make a .call file and call a cellphone or anything directly then run an agi script to dump the user in a conference if they select to


Can i use the Manager API to call the AGI
All the sales cell number exist in a system. So if I can trigger a agi whit information agifil.agi (arg1 arg2 arg3)
arg1 = cell number to be call.
arg2 = conference room to be dropped in.
arg3 = mode that the user will be in. talk or listening mode
I tried to find information about agi scripts. But I didn’t understood it. Ca any wane help me design the agi script or give my a url whit howto information about howto write the agi script that is going that I want it to do.