Awww. I hope the kitty comes back.
My cat, Misty, got out one day and didn't come back for 4 days. I was worried sick. She came back and was ok except for a few burrs caught in her hair.
Cats are really good about finding their way home. Try putting some food outside and leave the front porch light on and keep an eye out. From my experience, cats seem to come back when its dark out. Or try walking around the house with a flashlight at night and check bushes and stuff. Sometimes, they will stay nearby and be too scared to be out in the open.