Here's a set of 3 scripts I just knocked up.

They animate a group about a particular axis X, Y or Z.

Select a group and run the script. You will be prompted for a number of key frames to run over (defaults to number of frames in the scene)
The scripts add 5 key frames, rotating the group clockwise when looking from the positive end of the axis.

To rotate the opposite way, enter a negative number.

They should work with all versions from 5.7 upwards. Just Unzip into the scripts folder.

Rotate360.zip (2 Kb, 45 downloads) Rotation Scripts