Hello Masood,
Since the upgrade exams have been retired there is no single exam to take that will allow you to upgrade to 2003. However you still don't have to start from scratch. The shortest path to get your MCSA in 2003 is by taking 2 exams (assuming you took either the 70-210 or 70-270 in order to get your MCSA/E in 2000)
70-290 Managing and Maintaining a Windows Server 2003 Environment
70-291 Implementing, Managing, and Maintaining a Windows Server 2003 Network Infrastructure
After you complete those 2 exams you will have your MCSA in 2003. The reason why you need 2 exams for your MCSA is because your MCSA in 2000 will count as your elective exam, and your client OS exam would be covered if you too either 70-210 or 70-270
If you want your MCSE after that would take
70-293 Planning and Maintaining a Windows Server 2003 Network Infrastructure
70-294 Planning, Implementing, and Maintaining a Windows Server 2003 Active Directory Infrastructure
And than I believe you have to take one of the design electives, I am not 100% sure on this though, because on
http://www.microsoft.com/learning/mcp/mcse/windows2003/default.mspx#TRANSITIONIt says the skills do not differ that much between 2000 and 2003 so it isn't needed. However that would be if you are taking the two upgrade exams which are retired. Since that upgrade path is not open anymore I am not sure if you have to take them. Regardless here are the 2 exams to choose from
70-297 Designing a Windows Server 2003 Active Directory and Network Infrastructure
70-298 Designing Security for a Windows Server 2003 Network
Now some people might say just skip 2003 and go straight to 2008, this is up to you. If you are very familar with 2003 and have never used 2008 I would say go for 2003. Server 2003 will still by used for some time now so it wouldn't be a waste just because server 2008 is out.
Hope this helps and if you have any other questions let us know.
Eric
