As the name implies, ICQ or 'I Seek You' is simply a clever way of getting in touch with people. This small program takes the complicated work of finding friends, colleagues and people with similar interests across the globe, people who could be communicating by email, chat, SMS, phone or pager, and makes it as straight forward as calling across a room and starting a friendly conversation. The most popular method of communication on ICQ is instant messaging, enabling you to send a message that immediately pops up on an online contact's screen. ICQ also lets you chat, send emails, SMS and wireless-pager messages, as well as transfer files and URLs. ICQphone incorporates IP telephony functions enabling you to engage in PC-to-PC and PC-to-phone calls. Used in multiple-user mode, groups can conduct conferences or play games with ICQ. In fact, ICQ supports a variety of popular Internet applications and serves as a Universal Platform from which you can launch peer-to-peer applications.
The Internet Messaging service that provides instant contact with the greatest number of Internet users (according to MSN)...I do find it useful with those friends who are not on ICQ.
Communicate with Flexibility and Style.
Trillian is everything you need for instant messaging. Connect to ICQ�, AOL Instant Messenger(SM), MSN Messenger, Yahoo! Messenger and IRC in a single, sleek and slim interface.
This is not one I have tried yet but it has received rave reviews from various experts and seems to be very handy if you have to use different chat clients with different friends! If you wish to use video chat and have Windows XP, MSN Messenger is the one to use. If you do not have XP, Yahoo is recommended.