The 3.006 update is mostly to support the new Solo and Team local-hosted editions - download a disk image for a virtual machine, install it on your own hardware and access it locally. The release announcement for these is coming soon.
There are also three new examples files available, demonstrating the tuning process described in some detail in the recent articles Tuning 101 and Tuning STEP files.
There are also some minor tweaks to the UI, notably in the Examples menu to keep better control of the growing list of links and for touch devices, support for pinch-to-zoom for resizing the information panel as well as the 3D graphics.
The new update is already on the public servers and should load automatically as soon as you visit your allocated server - use Help -> About to confirm.