A previous poster was asking something similiar to you. No matter; read her post and ALL the replies. One suggests you don't paint (and gives reasons); another suggests otherwise (but doesn't say more).
In any event, take the enclose info to your friendly paint or formica retailer and ask what they think about painting formica countertops, or laminating over top of them with something else instead. Personally, I'd opt for the latter. I don't like the idea of paint on my countertop where food is concerned. See To Paint or Laminate On Top Of Formica. My best to ya and hope this helps. Also, I think Joe's suggestion is a start but if you decide to paint, you still need something that will adhere to the formica and hold down the paint. I suspect there's some type of primer or bonding agent you can buy.