Curious visitor

In the past few days, there's a cat sitting/sleeping on our doorstep. We don't know where it comes from, but there it is. Everytime I opened the door, it rushed in, trying to make itself at home. Then the "shoo! shoo! kitty!" ensued. We're pretty sure it's someone's house-cat, (although it doesn't have a collar) because it's extremely friendly- or just hungry and pretending to be friendly. Quoc fed it a few times. Me, I'm just hoping it doesn't adopt us, because we are not responsible enough for another life, at least at this moment. The cat's been visiting our neighbors as well, but no one's claiming it yet. We see it sleeping on the front steps of various houses, sometimes marching back and forth, meowing for food. I feel bad, but at the same time- hm.. it can be carrying toxoplasmosis! Who knows! So I peek out the window before I open the door, making sure it's not there, ready to pounce inside. I think we will call the animal control people to get it to a shelter. I'll sneek a picture of it when I'm brave enough :-)