Painting - Painting over painted cabinets

I am looking at purchasing an old farmhouse and am already planning and picking paint colors :P
I would like to paint the kitchen cabinets. They are already painted white. I would like to paint them a deep red and give them a distressed look. Do I need to remove all the old paint first?
How do I go about all this?

Well there are questions like what's on the cabs now etc but generally speaking and considering it's an old house....probably what's on them is oil based enamel.Then there's what you plan to use on them which is either again oil enamel or possibly a waterbourne enamel.Some use latex enamel similar to what is used on trim etc which will work but not be as durable.

You'll need to clean the cabinets well and be certain you get off any sort of kitchen residue like grease etc.Scrub them with mineral spirirts which is paint thinner then clean them well probably with TSP and water or a similar strong detergent product (not laundry etc but like Spic N Span) and rinse very well.Then scuff sand with very fine sandpaper especially if there is any gloss and remove any sanding residue.

Then use a better quality oil based primer is you're putting oil enamel on top or a better quality latex primer if you're using a waterbourne or latex on top.You can mix primer types and use latex over oil or oil over latex but you will risk lesser performance especially with latex over oil.Read the cans for exact compatability as it can vary.

Then top coat with your choice of product.Choose a better to top grade of enamel.Use better to top grade tools and brushes as cheaper tools will result in a lesser job regardless of paint.Shop where you will get help from knowledgeable saleshelp and know that big box stores sell paint based on meeting price points not quality levels.

You would only need to remove paint if it is loose or peeling etc.

Do I need two different paint colors, like brown under red, or would sanding and letting white show through be ok?

I'm no expert on the distressed look.I would think it depends on the look you want.If you want white to show through red I'm not sure a middle coat is needed.You don't need the brown for red to cover but you may need several coats of red as it can be difficult to work with.(There's a sticky in this forum about red).If you prime you might want to use a primer that is tinted at least somewhat red to help cover but if you distress then whatever color the primer is will show.If you want white to show then don't tint the primer,assuming you use one.