Hi,
There are two options:
1. Open source tool - You can use NUnit ASP for testing your asp.net 2.0 web applications. But the support is very limited, you may need to create your own mock classes if you are using any third party controls.
2. Visual Studio Team System, a great tool for testing your asp.net web applications. But it is not free.
So you can decide depending upon your budget vs effort required to build mock classes.
Thanks
Nitin Arora
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