Using .Net web pages in mobile devices

Hi,

1)I have a ASP.Net web page and i would like to port it for mobile devices 
like PDA and Smartphones. Is it necessary that i have to re-write the application in Mobile web application  If so, what is the advantage  

2) If i have to convert the web page to Mobile web application page, is it enough that i convert the usercontrols and the aspx pages to Mobile user controls and mobile web forms and use mobile controls in these pages  

3)Is it necessary that all the controls in the mobile web forms should be 
'mobile controls' 

4)What is the mobile control available corresponding to the table, div, 
span, dataview, hiddenfileds etc.

Thanks,
Lekshmi