When I worked at Sun I had an Accessline number and I loved it. I just started using GrandCentral from Google as a replacement and it’s not bad. It’s an invite only service right now, but totally free and you can get phone numbers in most areas.
One interesting use for me is to avoid long distance charges to Canada on my cell phone. If I have any of my friends up in Toronto, like Ken McPherson, call me on my cell I’ll be charged extra by Sprint. If I have them call my GrandCentral (GC) number, there’s no change in cost to them, but it only uses cell minutes. Much better.
Two of the cool features include the ability to screen and transfer calls. If someone calls you, you can tell immediately that it is from GC when you hear the GC operator. You press 1 to take the call, but can press 3 to send it to voicemail while you listen in. Should you decide you do want to take the call you just press # and pull it back. Very nice. While talking to someone who called your GC number you can press * and all other configured numbers will ring, allowing you, for instance, to transfer from your office phone to your cell.
There are a LOT more features. The call log, which allows you to bring up a map to your caller is slick.
Let me know if you want an invite.