If you have a gmail account you can make calls from your email to land lines. I use it for long distance calls. It's just like dialing and sitting at your LAN phone.
Positives:
1) It's as clear and reliable as your internet connection.
So if you've got high speed you've got clear reliable sound.
2) Calls within North America are free,
and for me to call Australia the rates are:
Australia - Other $0.02
Australia - Mobile $0.14
Australia - Satellite Services $0.17
I'm not sure what the rates are for Australians to call domestic.
3) Calls from one gmail account irrespective of location are also free. So if you're in
Australia have a gmail account and your friend in Canada has a gmail
account you can talk all day and it's free. Just costs your regular internet
connection.
What you need is:
A) a gmail account - free
B) a computer headset. I use
ClearChat. Got it for $18 Canadian.
C) Credit card to add credits if you're call isn't free.
Negatives:
1) Requires a computer, but if you have a laptop and wireless it's basically like having a really big cordless and a LAN line.
2) If your internet is glitchy or your computer is slow your voice can cut out.
3) Uses bandwidth, although in my experience not much.
Also, you can't use it for emergency calls.
Where it's the internet the police/ambulance can't triangulate in on your location.
It's a good option for people would normally use a LAN line or people who go through a fair bit of long distance minutes.