If I decide to not move into Apartment after dep. & signing contract, is that considered breaking lease?

For example, I put down a deposit and sign contract in Janurary 2008 for a lease to begin Feburary 2008 - Feburary 2009. Let's say I decide to not move in Feburary 2008 and notify in Janurary 2008 . Is that considered "breaking the lease" and forcing me to pay all the rent?