When it comes to making free calls across the internet using Voice over IPtechnology, Skype is certainly leading the pack. With almost 26 million peoplehaving downloaded the software, Skype is the most used free internetapplication.

Developed by the people behind the file-sharing service Kazaa, Skype offersfree internet telephony with another PC user as long as both have the Skypesoftware.

Of course, you're not limited to making calls, either. If you can see anotherSkype user online, you can request a text-based chat, in the same manner as youwould through Windows Live Messenger or similar applications. If they're not attheir desk, they will see your message as soon as they return.

This is the official release of Skype 4. New features include a brand newuser-interface, improved alerts, better audio clarity, an improved method ofmanaging multiple chats and much more.