Losing Weight

Well, if you wanted to maintain, and you are lightly active
I.E. you do a job that makes you walk a little, like around the office,
and you work out say 2 to 3 times a week for an hour or less at a moderate pace.
you should be at about 1925 calories or so.

If you want to loose weight at a 1 lb a week clip (pretty decent amount)
then you should be at about 1425 or so. If you are more active, then this will go up by a few hundred calories.

This DOESN'T include calories you add from exercise.

Example: say for 1425 calories without exercise
and today you do 1/2 an hour of moderate (say 72% of max heart rate) cardio
you probably burn about 300 cals or so (top of my head here)
So you could eat 1725 cals and still be loosing 1 lb per week.

some Notes:
1) You won't see 1 lb every week, this is because your body is a dynamic system, some weeks it may divert energy to making muscle (which would actually increase your weight, but is still a good thing), some weeks it may burn fat but you measured at a time when you had a lot of water in your system so you don't see any loss at all or even a gain. Not to worry, use other measurements besides the scale, I.E. waist, chest, hips, arms sizes. Body fat %, How you feel after you work out (exhausted, or tired) compared with how you felt last week for the same amount.

2)It may seem like too much, but trust us, it is where you want to be, you can tweek a little to fit your needs/schedule, but really you have to give this a good 3 months minimum to see consistant results. Weight loss is long term, and should almost never be measured in weeks or days. Some see it faster then others, but 3 months is a pretty good judge of whether it's working for you or not.