MSN Messenger is an instant-messaging program that notifies you when your friends are online so you can send messages or chat with several friends at once. In addition, MSN Messenger notifies you when you have new e-mail in your Hotmail account and allows you to access your inbox with the click of a button. You have full control over who can contact you and view whether you are online. At any time, you can see a list of all users who have added you to their lists, and you can easily block them if you choose to do so. You can also invite someone in your list to meet over the Internet
or to play an Internet game using NetMeeting. The program will even notify you when someone you are communicating with is typing so you can avoid overlapping messages.

Favorites and groups
Put the people you chat with most at the top of your contacts, so you easily see when they’re online. Want to chat with several people in one window? Just set up a group.

Customize
Show off your personal style with custom scenes, animated display pictures, and signature sounds.

Share photos
Look at photos together, right in the conversation window. And Messenger tells you when people you know post new photos on Windows Live.

Mobile and web
Using a public computer without Messenger? No problem! You can chat on the web from Windows Live Hotmail. Or, use Messenger on your mobile phone.

Homepage : http://www.msn.com

ICQ is an instant-messaging program that lets you communicate with friends and colleagues in real time. To seek out a friend on the ICQ network, simply enter his or her ICQ number, name, nickname, or e-mail address. Once your contact list is set up, you’ll be notified when your friends are online so that you can chat; send instant messages, files, and URLs; play games; or just hang out.

Get social
Get updates from social networks and chat with your ICQ friends
Express yourself
update your status and share your favoraites links and images through the new ICQ status box
Share pictures
share pictures of yourself and others wit the new ICQ picture sharing tool

Homepage : http://www.icq.com/