While it's not hard to find a free chat app that lets you IM and call friends on multiple networks, getting one to elegantly inform you of incoming chats and let you easily switch among open conversations is slimmer pickings. It may not be the most visually exciting app we've seen, but Nimbuzz IM does a fine job delivering features and alerting you to chats when you talk with friends on Skype, Facebook, Windows Live Messenger (MSN), Yahoo Messenger, Google Talk, AOL Instant Messenger (AIM), MySpace, ICQ, or Gadu-Gadu.
The app will buzz by default when a new chat line comes in, and also alert you in the notification bar. We like swiping between open chat windows, though this should also be an option in the Menu bar. If their chat network supports it, Nimbuzz can place voice calls and send photos, video, audio, and other files to a recipient.
Customizations are slim at this time, but chatting worked consistently, and as expect, in our tests.