Can I take my son out of state for vacation?

Basically, yes you can take your son out of state for a vacation. You should, however, provide the other parent with an itinerary.

While you may generally be entitled to know where your son will be for the wedding, such as the city and state, and how he will be getting there and back (e.g. by car, by plane, etc.) and who will be taking him (his father, a relative, etc.), you would not generally be entitled to a list of whom will be attending the wedding. If he provides you with the general location (city, state) information, the method of your son's travel there and back and who will be taking him, the dates and times of travel, and when he will be picking up and returning him, together with a method for you to communicate with your son while away (dad's cell phone, son's cell phone, a house phone where they will be staying, etc.), you'd generally be well-advised to allow your son to go. Much of this should be governed by the language of any agreement between you and any existing court judgment or order on the subject of parental responsibility and timesharing. Consult with an attorney to discuss the specifics of your situation and your options.