Our living room is contemporary, and our brick fireplace is out of place. I don't want to change it, just paint it a light tan that matches with the rest of the room. Can someone please tell me what steps I should take to paint it? Please let me know if how I should clean, sand, prime, etc., it. I'd like to paint it in Latex. Our house/fireplace was built in 1988. It is a typical New England red brick fireplace. Please write soon if you can. I'd like to paint it before it gets too cool outside. Thanks so much!!!

I would just get the dust off with a shop vac as far as preperation before painting.
Then you will need to prime it with an acrylic enamel undercoater primer which will seal it better than a regular drywall primer. The finish paint can be the latex topcoat of youe choice and plan on putting two coats on to get an even finish.

If the brick is shiny, like it has been laquered or polyurethaned, does this mean I need to prime it with an oil based primer? Anything else special I need to do? Thanks.

Yes I would go with an oil based primer to be sure you don't have adhesion problems down the road.