Thanks to our founder for recommending me. As it turns out, I have an answer.
Yep, there are companies that specialize in product placement. They are quite expensive. The way they work is the prodCo (you) will pay them a fee and they will do all the leg work. They then take a small percentage of the fee the companies pay the prodCo if it's more than the fee the prodCo has paid. The advantage is they already know what companies are looking to have their products in a movie and what new products they want to push are available. The disadvantage is companies aren't willing to pay to have their product in a small movie. You might get products in your movie, but you will pay for them.
If you are looking for product placement as a way of getting extra money for your production - you want Coke or Pepsi to pay you to include the product - you will need a high profile film. Major theatrical distribution will be a key. Coke or Pepsi wants James Bond to pick up a can, take a drink, utter a satisfying sigh and then use the can to disarm the bad guy. It's not to their advantage to have your lead detective have an ever present Diet Coke on his desk.
If you are looking for product placement to enhance your production value - the detective drives a 2008 Mercedes - you will also need a film that is going to see some kind of theatrical release or the actor playing the detective will need to be someone the general public knows. Occasionally a company will provide a prop like this free of charge, but the money you will pay to a product placement company won't really be worth it - much better to contact the company personally.
If you want the rights to use Coke or Pepsi logos and trademarks then a product placement company isn't the best way to to it.
Maybe more info than you need - but it might be helpful for indie filmmakes in general. Do you have a project that fits? My ex-girlfriend works for
Motion Picture Magic in Burbank. If you do, I'll be glad to make the introduction.