Ask: Good phone number service providers for startups?

My co-founder and I are looking for a convenient phone number service. We don't mind using our own cell phones to answer calls, in fact it'd be easiest at the moment since we don't have a good logical spot for a land-line. However, we don't want people calling our business number to hear our personal voice mail messages. Ideally, what I'm looking for would be a single phone number that would load balance or ring on whatever cell phone numbers we need it to. If the call is not answered it would not go to our voice mail, but instead to the company's voice mail. I just imagine this service would be cheaper than a full blown PBX or something. Are there any services like this, or services that have worked well for other small start ups? Thanks