Can someone guide me to a post on calories?

I know there are good ones out there on determining caloric needs, but I'm not sure what to search.

I've been eating 1,200/day since 1/16/12 without exercising. I started C25K on Wednesday and am walking 12,000 steps/day. So I'm way more active than I was before. I'm nearing maintenance, and I know I'm eating below my BMR of 1475 now, and definitely below my TDEE.

I still want to lose about 30 more pounds, but am also working on building lean muscle and getting fit.

Will one of you awesome losers please post a link to an article or post on eating the correct amount of calories without starving myself and still losing??