Download Miranda IM
Miranda IM is an instant messaging client compatible with Windows Live, Yahoo Mail, AIM, ICQ, QQ and many others. This program is super light; it consumes less than ten megabytes of memory. Although being so light, its interface allows a lot of the typical functions of other chat clients, such as sending files, profiles, conversation history and more. Also, it is very customizable, so you can play around with the features. If you are looking for a light and simple instant messaging tool that allows you to have all your contacts in one application, Miranda IM is definitely the one.