Check out Google SketchUp, doesn't take long to learn at all: http://www.quirky.com/forums/topic/7457

OMG thank you very much! Your the best! Although this is a little hard got anything else?

Spending 10-20 hours for a chance at making tens of thousands of dollars, or more, is hard work? I laugh every time people tell me that, you must have a very high paying job Matthew! That said, a lot of ideas don't need 3d to get the idea across, 3d would just be overkill; Microsoft Paint and Gimp are good 2d options.

@John....DITTO

Thanks John, I made a video of a miniaturized prototype for someone else's idea... which was kind of lame until I added pictures at the end, made with google sketchup. As you said, and I agree, "If I can do it, ANYBODY can!"
This isn't pimping, as it's not even my post, but you can see the video here:
http://www.quirky.com/ideations/148159

For mine, I paid a graphic designer to help me. Friend of a friend kind of thing but he worked out great. He's done graphics on some games that I'm sure some have played.

If there is a design school near you, students always need money, or you could try Craig's list. A lot of people here use Google SketchUp. I saw that in my area they teach that in night classes at the community college--check yours out, too if you are not a DIY person. The pictures don't have to be Rembrants, they just have to get the idea across. Things have won with sharpie on printer paper drawings.

Using a 3D program is a huge advantage in my opinion. The 3rd dimension introduces many more of those "light-bulb-moments". Experiment with Google SketchUp. Start off simple. Draw a line, then a square, then a box. Try making a pyramid, then a diamond. It gets easier the more you use it. YouTube has a tutorial for every SketchUp situation imaginable.

I've tried SketchUp before and got frustrated. It looks like I will have to try it again. My prototype does not do much justice for my vision.

I use Cheetah 3D. The program is very affordable and I found the video tutorials to be incredibly helpful. While my skills will never compare to the likes of Josh Wright or others, I can at least get my idea across. For the ideas I'm working on independently where the image really matters, I hire Josh (or buy a boatload of Ripples).

I use Google Sketchup. It is a very easy program. Actually, it took me a day or two to learn its basic and design my idea sketch with it. There is video tutorials on how to use it. Here is the link:
http://sketchup.google.com/intl/en/training/videos.html