I m looking for a tool to automate .Net application. I have checked various web sites and forums but what I am looking for, if someone have any compiled results from their research which can help me in my search.
I am assuming that you want a function testing tool. QTP is one of the best. It also has a .Net add-in, which might not be needed. If the GUI is truly a .Net then there will be .Net specific tables and objects, but most application can be tested without the plug-in. Even WinRunner can test most of the GUI in .Net
Success is the ability to go from one failure to another with no loss of enthusiasm.
~ Winston Churchill ~
Many of the tool makers support .net - QTP as Rich said is one of the best - However a quick way to identify if a tool will work on .Net is to call the vendor if the information is not on their website.
Compuware and Certify also work well.
Also try searching the .net forum - there may be some good information there.
I have not failed. I've just found 10,000 ways that won't work" --Thomas Edison
Have you evaluated TestComplete? It's much cheaper than QTP and may suit your needs.
If you are on a budget you'll also want to make sure that automation will bring you a return on your investment.
Depending upon the type of .NET app you are testing there may be some open-source tools (http://www.opensourcetesting.com) or you could use the .NET framework itself to automate your testing. Do a search for "Test Automation" on the MSDN website (http://www.msdn.microsoft.com) and there are a few articles that might be of interest.