datetime query issue

I'm not sure how to go about this: I want to find all rows with a timestamp
between, say 6 a.m. and 10 p.m. for any number of days. The column format is
datetime. How do I extract the 'time of the day' information from this
column? What I can think of is to create a view for every single day where datetime
is > 6 and < 10 and then another query on all views together but that doesn't sound
very elegant and would be a real memory hog for a large number of days.

Any better ideas?

Thanks

Frank