With both pregnancies our families found out the same day we did, in fact, during this one, DH and my dad were in the same room when I told DH that I was expecting. It was really sweet actually, because my dad happened to be visiting from the States on Mother's Day. Since we were trying, DH and I had a chat before he came about if we did get good news that month, if he wanted me to talk to him alone first or if he wanted my Dad to be able to know too with him, he chose the latter as we're both close to my dad.
So on Mothering Sunday, I took the test before anyone else woke up and got my positive. Everyone else woke up a bit after that and came down bringing me a Mother's Day gift and cards. I then turned around and said, "I know this isn't the norm, but I have a Mother's Day gift for you too," and gave DH a little box. DH opened it, and looked; Dad asked what it was and DH calmly explained that it was a pregnancy test.
For some strange reason, he thought for a minute that I had found the pregnancy test from our first daughter and given it to him as a reminder. He was sitting there thinking what a strange thing that was for me to do, when suddenly we saw comprehension dawning on his face, and he held me and cried with joy on my shoulder. It meant so much to me to share that moment, and I believe my father was so touched to be a part of our joy and see the love my husband has for us as a family first hand. It was one of my favourite memories.
As for "trying," my family is much more family oriented, and they all knew, especially as my sister and I were both trying at the same time, but we never told DH's family that we were trying. That just felt weird, so they found out when we were expecting.