After reading Ewan gush about it, I realized I needed to check out this Nimbuzz thing. It sounds really familiar, like I might have checked it out a while back, but I don’t remember, so I went ahead and pulled up the site. There are three components, one for mobile (with a native S60 and a java client), one for your PC (Mac users are forced to use a web-based version) and a Widget you can stick on Facespace or Mybook or whatever.
The native S60 client completely rocks, first of all. It integrates all of your IM protocols in one place, for free. 
You’ve got support for AIM, MSN, Yahoo!, Gtalk, Jabber, and ICQ. Skype is also there, for chat and voice calls, though, like the Skype beta client, voice calls get routed over the cellular network, not as true VOIP calls. However, there is an option to make the call as an Internet Call, if you have VOIP such as Gizmo or Truphone setup, which is very convenient.
The S60 client has a clean interface, and shows the appropriate icon for each service that you’re connected to. The contact’s status is shown, so that you know who’s available, and there’s an option to hide your offline contacts. You can also send all sorts of things, including photos and more importantly, files, to your IM contacts.
I would highly recommend Nimbuzz if you’re looking for a free IM client for your S60 handset. It’s really easy to use and supports all the major IM protocols in a nice interface.
You can download the mobile version either to your PC from Nimbuzz.com, or you can go to get.Nimbuzz.com on your phone’s web browser to download directly to your phone.
