This is key. stevenwei, you need to get your butt into some restaurants and test this idea out. I work with restaurant owners and workers all the time. They're loud, brash, and won't hesitate to tell you exactly what they think of you (and your product) to your face.
Spend a day in as many of the restaurants in your area as possible and request a meeting with the owner. Most of the time you'll get turned down, but take what you can get.
Ask them about their current website and if they have any issues. Talk to them about smartphones and try to understand how they perceive their problems. Take lots of notes. Then, use the words the restaurant people did on your site. It may seem unclear to us on HN, but if it speaks to restaurant people that's all that matters.
Great advice, and that has been our experience as well.
I'll add another citation. Although I would love to find more recent numbers, as I bet the percentage has jumped since then.
Great idea for the before and after videos...although on a Flash site the 'before' video won't be particularly exciting. :)
Anyways, the point is that you're not marketing to the smartphone users. You're marketing to people that probably don't have a smartphone, and may not know how people would use one to discover their site. Showing the different paths in a video or chart would be a good idea. Better might be to set something up with an existing customer with a horrible, flash-filled, pdf-menu'd main site. Get them to agree to let you post a video of what it was like before they got you, and how unusable the site is, even if you somehow get a direct link to the pdf menu.
Disclaimer: I'm not a businessperson or a restaurant owner.