This is a bad idea. Damo, I worked in a pizzeria for 3 and a half years, it's probably THE most competitive industry with very little money to be made. I think it ended up that way because it's a job where cheap immigrants can start out or start businesses.
I wasn't in a well known chain though, but still. For some reason most of the owners were Arabs and most of the drivers were eastern European.
The most money to be made is in blue collar areas, because downtown students/innercity people are cheap and you get trouble with crime (drivers beaten up for pizza or people take without paying), while in upper middle class areas people just don't order enough.
Blue collar areas you can make more money, as it's much more popular without much BS.
You better have tons of patience, people waiting for food aren't like people waiting for books or equipment, they can get nasty by their hunger.
I got regular business threats, personal bullshit, even death threats, people try and con you with stories of cold or wrong pizza then you go there to pick it up and almost all eaten, giving wrong addresses or expecting you to know the address if they're in some building, had one guy almost got in a fight with because he ordered a plain pizza which to him meant with pepperoni, students drunk or high as shit calling you every 2 minutes wondering where pizza is and telling you to hurry up constantly. Man, I could go on and on.
Hours are often til the am if you want to keep up with competition. This is the last business I would go in, seriously.
If you're really set on the food industry (and I hope you have experience because I've always believed you should stick to what you know) then try something fresh, like Greek delivery or something, that seems to be getting popular where I am and I'm sure the clientele is better.
Good luck and if you've actually been and done this business and want back in, you're a crazy man.