ASP hit count?

[DKCK]

SELECT Count(Tracking.IP) AS CountOfIP, DatePart("m",[date]) & "-" & DatePart("d",[date]) & "-" & DatePart("yyyy",[date]) AS Expr1
FROM Tracking
GROUP BY DatePart("m",[date]) & "-" & DatePart("d",[date]) & "-" & DatePart("yyyy",[date]);

The above SQL statement works fine for what I am trying to except I only want to count unique IP addresses for each day.

Unique won't work because each record is already unique. Any ideas?