We had our first frost last night. I have had my house plants outside since early spring, and didn't even think about them and the frost. They are sitting right next to the house and there is a tree overhead. I'm wondering if they are going to be all right...

Houseplants don't respond well to frost. Why don't you bring them indoors ?

Depending on the kind of plant, they may be all right if you bring them in and make sure you give TLC. Spider Plants especially are resillient. I have one that I did the same thing to a few years ago. By the time I got around to bringing the poor thing in, it was nearly dead. Fortunately, with my limited plant skills, I managed to keep it alive, and it's doing wonderfully.
Good luck