Hello Santhosh,
There is not a prerequiste for exam 70-528, you can take it as your first exam.
But by passing only 70-528, you will not gain any certification.
If your target is to get "MCTS .NET Framework 2.0, Web Applications" certification, addition to 70-528 you should also take 70-536.
Exam 70-536 is a basic exam for every certification given for VS2005
Exam 70-536: TS: Microsoft .NET Framework, Application Development Foundation
I hope that is a useful and explanatory info for you
Microsoft Visual Studio Certification Paths
Free Exam Vouchers
Our true mentor in life is science