Advice: VoIP Internet Provider for Outgoing LD only?

I’m setting up a * server for a small business with 12 employees and I must assume 8 phones will be going constantly. Long Distance is 99.99% within the USA and is only 5% of total outgoing calls.

I’m wanting to use a VoIP Provider to save $ on in the USA long distance.

Here’s my questions…

  1. Do I need a “business” service or will a residential one be fine?

  2. Do I need several lines or will one line handle more then one outgoing call at once… I do not expect more then 3 at a time for Outgoing LD.

  3. Please suggest a good provider for what I want to do.