Forums are a great starting point!
Your going to get the best deal working with the internet sales team and doing all your negotiating from home. E-mail all the dealerships within 200-300 miles and tell them exactly what you want. Give them the model, trim level, exterior and interior color in order of what you want the most and what would do, what options you must have (ie: nav, leather, automatic), include all the information you can so when they get back to you it is with a price quote and not asking questions. When you send your e-mails be very clear that you are gathering internet quotes on this car and want to know how much below invoice they can go. Never shop from MSRP or sticker price...go from invoice price (found on Edmunds by building your exact car). All current rebates and incentive should come off invoice price and than go from there. For example if invoice is $23,000 but there is $4500 worth of cash rebates the price you are working from is $18,500. Typically a good point to aim for is $300-$500 above invoice but right now you can do better.
Once you get your responses weed out the ones that are too high and deal with the ones that you like the best (some will be friendly and some will just be dumb jerks and remember that this person is making money off you so if you don't like them just weed them out) and the ones who quoted the best deal. If a dealer 300 miles away gives you the best price and your local dealer is in the ballpark e-mail them and tell them that XYZ dealer 300 miles away is quoting you $XXX but you would like to keep your business local and see if they will meet or beat it. This is what I had to do on my car because we only have two local Acura dealers so the prices I got from Seattle area dealers really helped me get a better price down here.
Once you have your price quote set then you can talk trade in if you are trading in. If they ask before hand tell them you are not sure yet because if they know about a trade in it WILL affect the price you pay for your new car.
This is the jest of it but if you have any questions just ask and I can try to help more. I do all the car shopping for our friends and family and have never not gotten a good deal. You just have to start a couple weeks before you are actually going to buy.
I have never paid over invoice since I started internet car shopping. Even my MDX which was very hot when I bought mine and had only been out for a month I got a great price on by spending a couple weeks playing the dealers prices against each other.
Have fun!!