I am interested to find out if there are a set # of teeth on the ring gear for each of the different ratios? If there is, does anyone know the teeth # for the popular ratio's, or is there a formula to calculate it with?

Divide ring gear tooth count by pinion gear tooth count to figure out gear ratio.

Check out a hi-perf/race catalog such as Jegs. They provide tooth counts with the ratios in their rear-end section.

It's usually possible to "guess" the tooth count by examining the fractional component of the ratio. For example:
the reciprocal of .07 is 14 so a 3.07 must be a 43/14
3.08 is 37/12 or 40/13
3.31 is 42/13
I'll work up a simple table and post at my web site www.GeoCities.com/~68_chevelle (http://www.GeoCities.com/~68_chevelle) in the next couble of days.