Need advices in my telecom project

Hi all,

I am new in this forum and also new in telecom business since I am in the marketing field. I have almost no idea about what we can do with VoIP but I learn a lot actually going to such telecom forums.

I have a project that I want to launch in a few month or weeks and I have been in contact with some callback system or VoIP providers in the US but I am still confused on what exactly should I opt to run properly my project and I hope to get an answer or suggestion from you.

My client should buy a prepaid card to use my service and then I will be receiving international calls from mobile, softphone or Internet. I will need to manage the hardware form my computer to switch the calls to other phones anywhere in the world or using 2 ways or 3 ways conferencing. I will need a time record passed on the phone from each call for my employee billing.

As a marketing person I am very reluctant before buying some thing as well make sure that my service will reach my clients need at low rates.
Is anyone have an idea about were should I go into?

Oliver