In mouselook or whenever I used control + alt to focus on a prim for edit purposing my view would also rapidly spin. This made it impossible to work on projects and would get me very dizzy if I stared at the spinning for too long. As I had just updated to Windows 8 I thought this was the cause. Tried to re-install second life .... updated video drivers....cleared all setting...etc but nothing worked.
Then after changing display settings from (larger 150% to medium 125%) I happened to again try second life and ALL WORKED FINE WITH NO SPINNING.
I then set the display size back to 150% and the spinning was back. Returning the display to 125% again and all worked well and again no spinning.
This was a lucky coincidental finding but it seems to be definitely the cause of the mysterious spin problem on Second Life.
Give changing the display size a try and I hope that solves your problem also.
LawrenceW