Good Gear Guide
In Pictures: 12 open source tools every Windows ad...
Squiggle is a fun tool for smaller businesses that may not have Office 365 with Lync for communication. It's a server-less LAN chat tool that is ready to use the moment you install it. In addition to being an IM tool for your LAN (or across multiple LANs if you need, although you’ll have to use the Squiggle Bridge for that), you can use it for file transfer, voice chat, and more. It also has chat and status history, emoticons, audio alerts, and tray pop-ups (that you can turn on/off), among many other features.
In Pictures: 12 open source tools every Windows admin will love