VPBuddy
This is similar to ICQ but much simpler, very basic.

To install and set up: Click on the "VPBuddy" link above to download the file to your hard drive. Remember where you saved the file. After it is finished downloading, go to where the file was saved and double-click on the file. It will install. Enter your e-mail address and any password you want to use. Next, restart your computer. Next, to add a person, click on "Add". Enter the person's name you would like to add and then their e-mail address. My email address is beccaj@us.ibm.com -you have to use this email address or you won't know when I'm available.