Yes they are allllll scams! I do inventing (amatuer still

) but you gotta make a prototype. I have a couple that I am working on, and its really a step by step process.
I recommend building one yourself and saving up money to get a legit one made down the road. It will cost you around 1,000 dollars or so to get one printed, or made other wise. (this shit is pretty cool; model making)
http://www.zcorp.com/documents/259_650Video.wvx
Then, when you got a legit working product, you gotta sell it. Make a list of companies in which your product would fit, ie tongue condom= durex (props to whose idea was that in another thread, gold, haha)
Once you gotta a list of the companies, you need to find THE MAN within the company. This is the guy who handles new products or is in charge of development; every company has one. You need to get him on THE PHONE!
First you sell him on a 15 minute meeting. This is where you present your product idea through a presentation. Harvey Reese has a good book on the process of getting your idea out there. PM me if you have any more questions. This is a process I am in the middle of discovering myself, but have been working at it for a couple years now, Good Luck