You can use MSN Emoticons with in any Messenger i.e MSN Messenger 6.0 - 6.1 or Higher, Yahoo Messenger and AOL Messenger.
You can also use Emoticons with in your Discussion Forums.

Download Aliens Emoticons

Method: How to add a emoticon to MSN Messenger?
* Save(right click and "save image as") a emoticon of your * choice to your computer
* Open a chat screen in MSN Messenger
* Click on the smiley(below) and click "My emoticons"
* Click "Add"
* Click "Find Image"
* Select the emoticon that you saved to your computer
* Add a keyboard shortcut
* If you like you can add a name too, this is not required.