It's difficult to know your exact needs, but here are a couple of things
that may help.  Open the query in design view.  In the Criteria row in the
date field put something like:

Between [Enter start date] And [Enter end date]

This will let the user choose the date range.  If you want specific dates:

Between #6/1/06# And #8/1/06#

Note that both dates will be included in the resulting set of records.

In a report you can set the Running Sum property of a text box to Over Group
or Over All.  Use the former if you have grouped records in your report.
For instance, you can group by month, then find the time for all records
within that group.  If you need to see the individual time in each record
you can add two text boxes bound to the Time field:  one with Running Sum
set as described, and the other with Running Sum set to No.  These settings
are all on the Property sheet, by the way.  If you don't want to see the
running sum next to each record, you can hide that text box (I'll call it
txtTimeTotal), and put an unbound text box into the report footer, with its
Control Source set to =[txtTimeTotal]

If you need something more specific, you will need to provide more details.
If anything about the description is unclear, post back.