Mikogo is a freeware, cross-platform desktop sharing tool. Starting with the latest version 4 - released a few days ago -, Mikogo is also available for Linux, in addition to the already existing Windows and Mac clients. There is also a web client but it lacks most of the Mikogo features so it can only be used for viewing.
Mikogo can be used for web conferencing, online meetings, presentations or remote support and comes with built-in file transfer and chat features. It doesn't come with native audio conferencing but it does support it through regular phone calls. For more info, see the Mikogo audio conferencing page.
What's really cool about Mikogo is that multiple participants can join a session and you can easily switch who has the control or which desktop is used for the presentation. There's also a a built-in recording tool so you can easily record your sessions.
Just like in TeamViewer, the connection is made based on a conference number so you don't have to know the IP address of any of the participants. This is an important feature because it makes using Mikogo a lot easier and works even if multiple computers share the same public IP.
Also, since security is important, you'll be glad to know that Mikogo uses 256-bit AES encryption for the desktop client and the Mikogo website uses 128-bit SSL encryption.
The Linux version of Mikogo still needs some work: the remote keyboard combinations feature doesn't work yet and the user interface doesn't integrate too well with the desktop. Also, some features are unfortunately only available for Windows, such as the whiteboard or the option to adjust the speed / quality. But this is the first Linux release so hopefully these features will be available in the Linux client soon.
You're probably wondering about the speed: well, it my test (I've only tested it on Linux!), Mikogo was kind of slow, compared to, let's say TeamViewer. But this may be related to my Internet connection so I can't really give a verdict here. But Mikogo comes with a lot of cool features so you should really give it a try - if you do, let us know how it works for you!
Download Mikogo - to use Mikogo on Linux, download the archive, extract it and double click the "mikogo" executable.
Thanks to Genbeta for the news!