Making application database independent ??

I have a web application using ".NET Framework SQL Provider". My all queries are designed in the datasets in design view of VS2005.

Now I want to make my application database independent, so what changes I have to make?

I will change the sql data provider to a "database independent .Net Provider", after that, DO I NEED TO MAKE ALL DATASETS AND DATATABLES AGAIN IN DESIGN MODE OR THE SAME WILL WORK. 

(i have taken the "database independent .Net Provider class" from the articles availble for making the application database independant)