I'm going to be setting up VoIP for a small business that is expected to grow rapidly. I don't really understand much about VoIP other than it's a telephone system that works over a regular network (intranet/internet) rather than over the POTS.
My primary question is how should this be setup? I know there are a ton of providers out there, there's IP PBXs, and even simpler solutions like Skype; what is the way to go? I want maximum flexibility and control over what features the system has. I want a very powerful and high quality phone system, but money is an object so it can't be too fancy.
If you know of any good articles that really describe how it works and the different options you have, that would be helpful. I just don't really understand it at a low level.
Also, if possible, I would like to support multiple locations. There are two building that are separated by a small driveway that will need to both have phones in it (the network will be joined so that's not really an issue) but there are a few people who will be working remotely, so if they could have a company phone with a four digit "extension" that would be awesome. Would that just be done with a VPN or what?