Originally Posted by x12media

This requires you to know C#

if you want to use systems like that, then there are many:
(not listed in any order)
1) phonegap.com
2) appcelerator.com
3) sencha.com

and many many more..

It all comes down to what you know the best to code in.

I personally dont use the middleware or convertors, I rather code in native for all devices I am deploying my apps too. (but thats me)