first off, welcome to the boards!! to you both :wave:
of course, it always varies somewhat, but june through labor day is always one of the busiest times of the year. if you are staying at a disney resort, you will be much better off in terms of crowds. make sure to take advantage of EMH and get to the parks early. if you are not staying at a disney resort, don't go to a park in the morning the same day it has a morning EMH, and get to the parks at least an hour before official opening time.
although you didn't address the weather issues, it will be hot, and june and july are the two months that get the most rainfall in florida. usually they are just 10 minute - 1 hour downpours though, and won't affect the vacation.
though it may be crowded, you should have no troubles getting a lot done on your vacation! enjoy your trip!