Why don't you try aMSN, latest betas support webcam and custom emoticons along with user pictures and a bunch of fetures that you wouldn't find on any other IM application ... get it here --> aMSN 0.95 beta
You'll find that Adium is another great IM multi protocol application... I use Adiium for AIM, Yahoo and a MSN account in which only have work contacts that doesn't require things like webcam and fun stuff... aMSN is which I use for another account with friends only... Try both get Adium at www.adiumx.com.
On Adium forums there's an aMSN section too so you can get more help about those applications.