Skype and other VoIP

Both Megan Fitzgerld and Emmanuelle Archer have posted about Skype, specifically and VoIP in general. VoIP stands for “voice over internet protocol,” and refers to any phone-type service that’s transmitted over the internet instead of over traditional telephone lines. Many companies offer VoIP service. One of the better known is Skype, which allows you to make free audio and video calls over the internet, and also offers several paid plans allowing you to call from your computer to regular phone numbers for a relatively low cost. With Skype you can make free calls over the Internet.
I have used Skype to talk to friends and relatives here in the US, and plan to try it to talk with a young man I know in France. You need a webcam and microphone to use the video feature, or you can do just audio, and it works fairly well.
I also use Vonage for my home phone service. For a reasonable monthly rate (about $25) you have unlimited calls in the US and Canada, and you can call foreign countries for free or for a very nominal per-minute fee. France, UK and most of Europe are free, and many other countries are only a penny per minute. Vonage offers a “soft phone,” where you can get a number that works with your computer, and you can use your computer to call anywhere in the world for the same or similar rates.
Obviously, the drawback to any VoIP system is, if your computer and/or your internet connection are down, you can’t make or receive calls.
Would love to hear comments from anyone who is using another VoIP system.