how to retrieve only last 60 min. data from a col

Hi Gurus,

I was wondering how could I select only last 60 min. or last 24 Hr. data from my col.?

Lets say I have something like:

Dw_Load_Dttm
2012-08-06 09:50:25.287
2012-08-06 09:50:25.287
2012-08-13 12:52:09.303
2012-08-13 12:52:09.303
2012-08-13 12:52:09.303
2012-08-13 12:52:09.303
2012-08-13 12:52:09.303
2012-08-13 12:52:09.303
2012-08-15 15:00:22.140
2012-08-15 15:00:22.140

So from above I only want with 2012-08-15 as the date.

Please help me with this.