Counting Popularity, Hour By Hour

I have a table that is recording hits to a website. Everytime someone views a page, the datetime of the hit is recorded in a field called hit_date_time. I would like to be able to come up with a query that will show how many hits occured on a given day or given days, broken down by hour.

The resulting table for two days would look something like:
Time Hits
1/1/01 12:00 1
1/1/01 1:00 23
1/1/01 2:00 54
1/2/01 1:00 15
1/2/01 2:00 14

I can't seem to figure out how to write the query so that I can take into consideration the date and hour of the event so that I can count it.

Thanks,

Eron