Skype 2.5 is the latest version of the popular peer-to-peer voice service. Skype is also a software-based VoIP service, but its free calls are limited to PC-to-PC phone calls, and the receiving party must also has Skype installed and be online. With SkypeOut, Skype users can call landlines and mobiles phone all over the world for a small charge based on usage (US users can now call fixed line phones in North America for free), while SkypeInSkypeIn gives you a real phone number which your friends can call you in Skype, literally. When you’re busy of offline, Skype Voicemail will takes the messages from the callers.
PCWorld gives good rating of 79 to AIM Phoneline and concludes that it’s a good deal for AIM users who intend to make tons of calls (domestic and international) from their PC. For Skype, PCWorld writes that it’s worth the upgrade if you’d find the incremental enhancements useful; great for Skype users who need voice chat rooms for very big groups.
After comparing AIM Phoneline and Skype 2.5, PCWorld says that either AIM or Skype is a good place to start. If you’re a fan of AOL’s instant messenger, then you might want to download the new service and give it a try. If you have friends and family that are already using Skype, then it’s certainly worth a try, too. Before you opt for either service’s pay-based plans, you should use the free services first, to judge call quality for yourself.
However, in PCWorld’s tests on AIM Phoneline and Skype 2.5, PCWorld found that Skype has more-usable service, offering better overall call quality, fewer dropped calls, and no annoying advertising.
Full Review (dead link)