Preferably national tv, it could be production and airing or either/or. Where do I start looking??.--Answer1:I would try going to the network that you wish to advertise ons website..--Answer2:Unless you have experience in this, you would start with a marketing/advertising agency. They would come up with the creative direction and script for the ad, cast actors, direct, film and produce the commercial and arrange for airing on networks appropriate to your target audience and budget. Just so you know, this will not be cheap.