Okay listen... Starting a business costs money... a lot of money. If you don't have the funds to overcome a year without income, you shouldn't be starting a business in the first place. If you are out of a job, I hope you saved money when you still had a job.
And read the second part of my sentence: involving investors. Maybe you can convince former businesspartners to invest in your company? Or maybe contact an ex-colleague who happens to be out of a job too?
You may not like the truth, but that doesn't change the fact that starting a business costs money. I considered the same thing when I was unemployed, and I almost started one too. But I took a look at the worst-case scenario (giving my current financial status at that time), and I realized that things could get very ugly if I didn't start making profit after the first 6 months. That's quite a short period, and given the economy at that time, I was not sure that would be the case. So, yeah, I know what you are going through. Ofcourse, if you already have an interested customer who's willing to spent his money on you for a year, than I guess you can take the risk.
You can also try to do some freelance consulting (team up with some big consulting companies if you have to). It allows you to make money, and gives you the freedom to start your company when your finances are looking better. Most IT freelancing jobs don't require a big investment (laptop+office suite software+some bookkeeping stuff). That's how Joel Spolsky of Fog Creek Software started his company, I believe... (do consulting to bring in the money, while working on his software product)