Hi
For build a IVR Solution You need hardware Card(Dialogic/ICON) and a software to call/recieve Intractive Voice Responces from target users. This can be XtendIVR or Graphical VOS
After this you need a telephone line/E1 line(Set of 30 phone lines) . Its depends on the scope of you business. for personal or short business single phone line is sufficient
My personal IVR field experience says that Dialogic and XtendIVR combination is the best
For more about hardware and coast you can follow these links
http://www.ivrsolution.9ix.net/
http://www.voxeo.com/
http://users.telenet.be/Asterisk-PBX/IVR.htm
http://www.xtendtech.com/ivr/
http://www.voicesaver.com/insight_ivr.php
http://www.voiplogic.com/content77.html?gclid=CKau3vzDppcCFckrpAodkylu_A
http://www.dialogic.com/default.htm
http://www.voiceguide.com/
Enjoy have a nice day
Suren
http://www.finestmail.blogspot.com