I used to use flyerzone for printing (A^ worked better for me) but now print my own by the 10K. They used to be the cheapest I could find but can't vouch for that any more.
Design wise, do it yourself - but get it proofed, the last thing you want to do is pay out for leaflets then put a sticker over an error on every one, like a phone number. Simplicity is the key IMO so don't think it needs to be anything fancy - you don't need to be a graphic designer to make a successful leaflet!