Self employment tax deduction question?

I am an independent contractor and work from home for another company and my job is 100% on the computer. So in 2009 I bought a laptop to work and some just told me that i could have deducted that as a work expense for the 2009 taxes but I didn't know...can I still deduct it from 2010 taxes or is it too late? What else can I deduct as a business expense working strictly at home and on the computer. Can I deduct any portion of rent, utilities or internet???