A lot of it depends on the laws where you live. However, every lease I have ever signed has language that prevents early termination and/or subleasing without some kind of buyout or penalty.
I don't suppose you have talked to your landlord yet? In some cases they may let you out if they can turn it around pretty quickly. On the other hand, if you live in a big complex, management may not even realize it if you do indeed sublease. Just remember you are responsible if your tennant is late.