Is your company using MS Lync as a chat/communication service?
You can connect to it with Pidgin using the SIPE plugin.
Text-chat and file-transfers work, but I havn’t found a way to get audio and video conversations to work under Fedora 17, unfortunately.
One tip:
If you see this error in Pidgin:
Web ticket request to https://YOURDOMAIN.com/CertProv/CertProvisioningService.svc failed
Then likely your Windows domain password has changed.
Just edit your SIPE account settings in Pidgin, enter your current password, and you’re good to go.
Update: Under Fedora 19 the audio and video work.
But I only managed to receive incoming audio and video calls. Outbound audio and video calls don’t work yet.
Group-chats work too.
Application- and screen sharing don’t work.