I am roomating with 4 people, and I have not signed anything?
If you have a conscience, you would want to give your roommates a couple or even better a months notice so they can find a replacement. On the legal side, since you didnt sign anything then you could leave now, but just think if you were the roommate who kept living there and now all of the sudden a person leaves and now you have to find a way to pitch in to cover that persons rent and /or utilities and you didnt have that extra money. Try to offer your roommates a prorated amount of money to cover the number of days you are there until you leave. Hopefully this helps you.