OK so I have fraternal twin girls, what are the odds of having multiples again?

In general the probability of having twins is 3%, but if you've already had a set of twins the odds of the next pregnany resulting in twins rises to about 14%. Some good info on the subject here: Odds of Twins - Increase Your Odds of Having Twins or Multiples (http://multiples.about.com/cs/funfacts/a/oddsoftwins_2.htm)