There are a lot of those webapps which can be used to log into Skype, Gchat, AIM, and other services, all at once. And Imo.im is in a way one of them, yet with its new look, mobile apps, and Chrome desktop notifications, it may be the slickest web chat client around.
Imo can ping Chrome users about their incoming chats so they have the same kind of presence as if using a standard IM client like Pidgin or Adium, just like Gmail’s desktop notifications. The service stands alone, too, in letting you record 30-second voice clips and send them to IM users with an instant download link.
When you’re on an iPhone, iPad, or Android, imo has you covered there, too. Here’s their iPad app in action: