TSQL: Howto add a char to a select statement

I have the following statement

SELECT id, descr from mytable 

which returns

1, ‘Test1’
4, ‘Test4’
6, ‘Test6’
8, ‘Test8’
22, ‘Test22’

Now I want the display to Add a sequential character to the first 4 results…

‘A’, 1, ‘Test1’
‘B’, 4, ‘Test4’
‘C’, 6, ‘Test6’
‘D’, 8, ‘Test8’
”,22, ‘Test22’


Edit: Would prefer a SQL Server 2000 example if possible.