Loading Data Aggregated to Date into Fact Table

I have following source table:
Source Table
ID App_Version Os_Version Date
9123305 2.5.2.60 Windows NT 5.1 2/15/2009
9123306 2.5.2.60 Windows NT 5.1 2/15/2009
9123307 2.5.2.60 Windows NT 5.1 2/15/2009
9123308 2.5.2.60 Windows NT 5.1 2/15/2009
9123309 2.5.2.60 Windows NT 6.0 2/15/2009
9123310 2.5.2.60 Windows NT 5.1 2/15/2009
9123311 2.5.2.60 Windows NT 5.1 2/15/2009
9123312 2.5.2.60 Windows NT 5.1 2/15/2009
9123313 2.5.2.60 Windows NT 6.0 2/15/2009
9123314 2.5.2.60 Windows NT 5.1 2/15/2009
9123315 2.5.2.60 Windows NT 5.1 2/15/2009
9123316 2.5.2.60 Windows NT 5.1 2/16/2009
9123317 2.5.2.60 Windows NT 5.1 2/17/2009
9123318 2.5.2.60 Windows NT 5.1 2/17/2009
9123319 2.5.2.60 Windows NT 5.1 2/17/2009
9123320 2.3.1.92 Windows NT 5.1 2/18/2009
9123321 2.5.2.60 Windows NT 5.1 2/18/2009
9123322 2.5.2.60 Windows NT 5.1 2/19/2009
9123323 2.5.2.60 Windows NT 5.1 2/19/2009
9123324 2.5.2.60 Windows NT 5.1 2/19/2009
9123325 2.5.2.60 Windows NT 5.1 2/19/2009
9123326 2.5.2.60 Windows NT 5.1 2/19/2009
9123327 2.5.2.60 Windows NT 5.1 2/20/2009
9123328 2.3.1.40 Intel Mac OS X 10.5 2/20/2009
9123329 2.5.2.60 Windows NT 6.0 2/20/2009

I want to insert aggregated data into my fact table which should look like following. It should aggregate the data per date per os_version per app_version and then count IDs for each group.

Sample Fact Table

Date OS_Version App_Version CountID
2/15/2009 Windows NT 5.1 2.5.2.60 9
2/15/2009 Windows NT 6.0 2.5.2.60 2
2/16/2009 Windows NT 5.1 2.5.2.60 1
2/17/2009 Windows NT 5.1 2.5.2.60 3
2/18/2009 Windows NT 5.1 2.5.2.60 1
2/18/2009 Windows NT 5.1 2.3.1.92 1
2/19/2009 Windows NT 5.1 2.5.2.60 5
2/20/2009 Windows NT 5.1 2.5.2.60 1
2/20/2009 Windows NT 6.0 2.5.2.60 1
2/20/2009 Intel Mac OS X 10.5 2.3.1.40 1

I am completely new to databases please guide me to solve this problem. It very urgent plz help.

Regards

Harris

INSERT INTO
SELECT ID, App_Version, Os_Version, Date, COUNT(*) CountID
FROM
GROUP BY ID, App_Version, Os_Version, Date;