
The fun using Skype is that you get to talk to your friends much easier and frequent than you were used to. I got to talk to my buddy in Idaho just about every couple of weeks while we used to write letters (those were dinosaur days by the way) and e-mail. Since Skype is also an Instant Messenger like MSN Messenger or ICQ, it's also easy to track who is on-line or not. This is obviously not available for your contacts in the list who only have regular phones.

There are similar programs now which work pretty much like Skype: Gizmo Project, Yak and Jajah (what's in a name?). Even Google has a program called Google Talk and guess what, Microsoft announced to come with a calling option in their future releases of MSN Messenger. Skype has the largest user-base so far and it's available for most platforms including WIndows, Mac, Pocket PC and Linux. Others are only available for PC and Mac while a few are PC only.
** Update Feb 2006 **
Jajah dropped the idea of using a program to call your friends. Rather they changed their application to a web-page where you enter your phone-number as well as the person you want to call. Jajah takes care of the the connection between the two phone-numbers. You will be charged with Jajah's own proprietary rate which is obviously (supposed) to be a lot cheaper than you regular carrier.
This is an interesting solution to the ever fast moving world of VoIP. Jajah's solution bypasses the idea of needing a broadband internet connection as well as the hassle of having to install a new application.
Gizmo users can talk to GoogleTalk users and vice versa! We need more of these inter-compatibilty pacts!
Another VoIP-like program appeared in the arena: SightSpeed. This is a program similar to Apple's iChat in terms of just offering a audio and videochat rather than including options to call regular phone numbers (like Skype and Gizmo). Recently a Mac version has been released next to the PC version. SightSpeed seems to be a solution to a problem which Apple never (wanted to) solved: videochat with both Mac and PC users.