It's a little shocking to see some of the 'advice' on here.
What's your skill set?
Because, if you can't do basic HTML and Javascript then this will get rather frustrating - quickly.
At the International agency I work for, I'm using HTML5 and mobile JQUERY for portable devices.
Probably too
advanced for your needs.
-HTML 5
-
http://jquerymobile.com/
Also, you need to be savvy when developing for multiple devices:
-
Make a big splash on small screens
HTML 5
The benefit of this, is modern handsets are HTML 5 capable. You can build a web app and convert it to a native app without too much stress.
Whether it's for iOS/Android/Symbian or Windows.
Mobile JQuery
This allows you to replicate native style animations without having to learn Cocoa or other native languages.
Anyone can build you 'mobile site' but if you're going to do it properly then it's worth looking into it yourself. The mainstream web community advances at 5X the rate of the porn web community from what I have seen everywhere.
Finally - Be aware of limitations.
You'd probably be best served to start on a web app service, then transition to a native app service later.
Off-topic:
Whenever I see another wordpress blog in these forums, it sends a shiver up my spine.