a tax question

I would appreciate if you could give some suggestion for my situation.

I have a full time job and get W2.I am also a part-time real estate agent.Because of the the market in 2007, I have many gas expense when I drove to show client house,But I do not have many related income.I like to use TAXCUT software to do my tax.I am not if I can deduct the gas expense since I don't have many related income.How I can file my part-time job expense?

Thanks for your time and kindly reply.
Jenny