here's one way to do it, i'm sure you'll get other examples to choose from:
select CONVERT(varchar,datepart(hour,getdate()) % 12 ) + ' ' + CASE WHEN datepart(hour,getdate()) > =12 THEN 'PM' ELSE 'AM' END
--preceeding zero for HH?
select RIGHT('00' + CONVERT(varchar,datepart(hour,getdate()) % 12 ),2) + ' ' + CASE WHEN datepart(hour,getdate()) > =12 THEN 'PM' ELSE 'AM' END
--results: 2 PM
-- 02 PM
Lowell