Have you tried meebo.com? It's fabulous. It requires you to download nothing and works like a charm. At least, I like it. I do admit that it has a few hangups from time to time, but these never last long, and I'll just hop onto AIM Express while the little crew of computer people that I imagine working 50,000 miles away fix the problem, and then I'm back online. You can put MSN, Yahoo!, AIM, Facebook Chat, and more, I've heard, though that's all I use, onto your account, and be signed into all of them at the same time.