They didn't tell you a date that they would notify you by? That would be odd...
I know that the deadline for returning swimmers to register is July 13 so you probably aren't going to hear anything until after that since it won't be until then that they know how many slots are available.
After that, the top how ever many slots have some period of time to decide before they make their way down their ranked list. My guess is that if you have heard anything by July 20th or so, you probably didn't make the cut.
Good luck and keep us posted!