yep - I've heard of them being called moon-bows....
Although, technically they are called 'halo's
Sometimes seen around the Sun too, it there is thin cloud.
There are quite a few similar phenomena....
A bright spot to either side of the Sun (usually seen in thin coud) is called a 'Sundog' - Sundogs are always 22 degrees to the side of the Sun.
Sun-pillars (as their name suggests) appear to be pillars of light pointing eother up or down from the Sun
Moon-dogs and moon-pillars are also possible, but rare.
Sometimes, what looks like an upside down rainbow may be seen above the Sun (22 degrees above the Sun to be exact) - this is called a 'circumzenithal arc'
As luck would have it, there's a pic of a Moon halo on 'Spaceweather' today - with links to explanations of the other phenomena....
SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids