ICQ
(I Seek You). A perfect utility! I use it a lot... well, Always, in fact!
Watch if your friends are online. No matter how they are online (eg. on the Web, with IRC or telnet...),
you'll see them, be able to chat direct with them, transfer some files to them. You can also send them URLs and
messages when they aren't online.
Download it from http://www.mirabilis.com.