While this message board it a great resourse, it isn't the only cruise message board out there. There is also www.cruise-addict.com
Cruise message boards are a great communitiy and source for information, but the best results come from specific questions, but as a true beginner, you might not know what questions to ask. In my opinion, I think a better way to start is with a cruise guide book, such as "the Unofficial Guide to Cruising", or one of the Frommer's guides to cruising. Also, a Travel Agent would be a good resourse for you to help you answer questions and more importantly, give you the cruise line brochures for those that depart from your port of choice. While you are at the TA, you might want to discuss setting up a group cruise, since you have at least 4 familys going. Just by setting up the group, you should get additional benifits, such as shipboard credits. Once you have 8 cabins booked, usually the person orginizing the cruise (you in this case) will get a "free" cruise, meaning one passenger will only have to pay taxes and port fees. You can share this discount with the whole group, or just us it youself.
The first step is to determin which cruise lines depart from the port you want to leave from. Since you want to leave from Phili or Boston, you will have a very limitied choice, as many more ships depart from a port in Flordia. Once you know which ships are available, you will have a much better idea of what to choose.
You do not have to get a "family suite". Most ships have cabins that will accomdate a third and fourth passenger. They come in almost all cabin catagories, from inside to balcony suites. A lot of this does depent on the cruise line and the individual ship. Holland Americe doesn't seen to have many quad cabins, if any, while Royal Caribbean usually has quite a bit.