Dave i think the easiest is cast your datetime as TIME datatype, but here's a quick example of the three i could think of:
/*
create_date TheTime CharTime108 CharTime114
----------------------- ---------------- ------------------------------ ------------------------------
2010-03-29 08:55:29.650 08:55:29.6500000 08:55:29 08:55:29:650
2005-10-14 01:36:15.910 01:36:15.9100000 01:36:15 01:36:15:910
*/
with mycte
AS
(
select top 10 create_date from sys.objects
)
select create_date,
convert(time,create_date) as TheTime,
CONVERT(varchar,create_date,108) As CharTime108,
CONVERT(varchar,create_date,114) As CharTime114
from Mycte
Lowell