I've been playing with VoIP for a while now. VoIP = "Voice over Internet Protocol" and it's essentially using computer networks as your phone network. Skype is a form of VoIP. The one thing I have against Skype is it's closed protocol that means only Skype things will work with Skype. The more open standard is called SIP, and lots of companies make software and devices that will work with each other through SIP. Our new office telephone system can connect to SIP in the same way it connects to our BT phone lines (actually, there's no physical connection as the SIP calls would come in via our internet connection rather than a physical BT line plug).
One of the downsides with learning anything new is the time it takes to learn. The downside with any communication network is that it's only as good as the number of people that are already using it (I have only a half dozen contacts on my Skype account and my MSN Messenger account).
My recent VoIP experiments brought me to the www.sipgate.co.uk website. They've really made the set up easy. I signed up for an account in less than 3 minutes. I downloaded their version of the X-Ten softphone. They've made it so that it downloads including your account settings. All I had to do was install, no settings to change, it worked immediately! Superb! Anyway, less than 5 minutes after discovering sipgate, I called myself from the office to my new sipgate phone. I picked up one of their free local numbers, so you can call me too on 01227 808060 from your real phone(s). If you already use a SIP service, you can call that number free by using whatever prefix you need to connect from your service to sipgate.
That means you can call me on one local number wherever I happen to have my laptop set up. At the office, at home, In a hotel while visiting suppliers around the UK or even if I'm working abroad. Therein lies the one problem, I need to have the laptop turned on for the phone to be working and available. The good thing is that SIP doesn't require a specific computer, there are devices that will connect SIP to your normal house telephone (and even let you use both networks together), as I said our office phone system already works with SIP (or will when I figure out how), my mobile phone has software that allows it be used as a SIP phone, our ADSL router will also let us connect a regular phone to the SIP services. You can also buy dedicated SIP phones from around 50 (and DECT cordless SIP phones are around 100).
I've still lots to learn about SIP and making it work. One little gadget I just found on the sipgate site is a snippet of code that may* tell you if I've got my SIP device connected to the internet..... may, or may not.