Are there any guidelines regarding which asp.net controls (e.g. GridView, UpdatePanel...?) should be avoided when developing a web application for mobile phones?
My application is going to be used probably in iphone, blackberry or android enabled phone, so I would like to know if there are known problems related, for example, to control renderization or javascript handling in these platforms' mobile browsers.
Also, usability guidelines regarding best controls to avoid / use would also be appreciated.
At this point there is no Web Forms project template for mobile in ASP.NET Web Forms but there is in the new MVC release:
Here's some info on creating mobile pages for Web Forms:
How To: Add Mobile Pages to Your ASP.NET Web Forms / MVC Application
Lastly, you might want to consider using jQuery Mobile.
As for controls to avoid? Definitely the richer ones like Calendar and GridView - but jQuery Mobile can offer you some options for the former...
You can use Modernizr for feature detection to better target specific mobile browsers.