Hey

Is it for Charity? If so, you might approach some printers and see who will either do it at 'cost' or better still for free! Some of them will do this if it is for a registered Charity.
If this is not succesful, try getting sponsership from Companies. Either one Company for the whole issue or a different Company for each individual Month. (sometimes this is better as it is cheaper for the smaller Companies) You would then put their logo on each month, normally small and along the bottom of the Calender. This certainly helps with the production costs. Obviously you will have to offer something in return and in this case it would be half a dozen calenders for the Boss! ooh! and a huge smile from you!
Photographs are important, so again speak to a Photographer and see if they would donate their services FOC. PM me for more details on this one!
Decide on the format you wish the Calender is to take. Is it one photo per month or just a collage and the calender part attached to the bottom!
If you have the photos before you make an appointment to see the printer that would help as it is the 'cute' factor you would want to play on!
Also, thinking about where you would distribute it to get the best return.
Available date is important as it is coming up for Crimbo and everyone needs a Calender for the New Year. Maybe approaching your local Card shops or Newsagents.
Once you have gathered all the outgoings, work out how much you would need to print (pre-orders are always good) and then calculate how much each unit would cost to produce and this will allow you to get a final selling price. Tip: times net cost by three is the usual.
You will have to show that the proceeds will be going to your Charity and have a place on the Calender for the Reg no.

Hope this gives food for thought.
(PS normally when producing a calender, one starts one year ahead. ie production in 2010 for 2012 Calender)

Carolyne