I think VOIIP is a phone service only, whereas what you're looking for is more a routing/voicemail service? Although there are probably Voiips that do both. Not sure. My company actually uses the service listed above, Gotvmail and we've been happy with them-- never heard of the others, but I know gotv offers the functionality you're referring to, a 1-800 number and forwarding to "extensions" -- each employee gets their own extension that can run to a landline, or mobile, or treo, or whatever. The nice thing about services like this is that it negates the need for a receptionist if you're a small company, and you can still sound professional with the personalized voice greetings. So, your employer is on the right track, I'd say, just check out a few of these options.