I just found out about a reasonably new program called Digsby. Its an all-in-one IM solution, but also incorporates Twitter, MySpace and Facebook. Its a neat way to have everything in one place in a neat page. Its free, which is always great and its pretty simple to get started with! Digsby also has one big wow factor which is that it seamlessly integrates the new Facebook chat!
Now, all I need is a mobile version of this and I will be in seventh heaven!