How do I repair a small hole in my shingled roof?

I went on the roof to do a routine inspection, and found that there was a small hole (about 3/4 inch to an inch) going through 2 (overlapped) shingles, and I believe it went through the roof. I'm not sure of the best way to attack this. Is there some repair kit at the home depot or something that I can pick up? Thank you.