Issuetrak - Issue tracking software for help desk and customer service
TeamViewer - TeamViewer lets you establish a connection to any PC or server within just a few seconds.
Deskun - Deskun is a Help Desk system inside Gmail. It enables you to support customers directly from your mailbox, manage projects, and use free features for Gmail.
mRemoteNG - mRemoteNG is a fork of mRemote, an open source, tabbed, multi-protocol, remote connections manager.
Kapdesk - Kapdesk offers support teams with a helpdesk software to streamline support tasks.
join.me - Instant screen sharing. Instant Aha!