How can I get rid of lizzards in my attic? Not sure how they are getting in, unless it is a very small (1/16 inch) crack around a vent. I hear them at night moving insulation out the way for a bedding area on the drywall (ceiling).

Where are you located? In North America noises like that are more often associated with rodents.

As to how they(whoever "they" are)could be getting in, a very common entryway is under the shingles and between the fascia boards and the roof decking.

Getting rid of them (if they are lizards) is most easily done with repellants to chase them out. Paprika works well and does not have a huge odor like chili powder nor is it as dangerous as napthalene(mothballs).