Forcing Null

So I have a table that does a count on ratings in a certain category. The problem is that I want a number to appear for each of the three categories, even when the count returns nothing. In other words, we have 3 rating types, "poor, good, and great," and I need a result for it, even if no one gave the category a poor rating. Now I figured that if I created a table (tblCateg) that just held the three categories (sCatDesc) and did a join on the other table (Ratings) with the column (IN_Category) that I needed, it would force the query to make all 3 ratings appear and a count for each. Unfortunately, this didn't happen. All that appeared was
---------
Great 17
Good 7
---------

I figure the query is just seeing the count for the Poor rating as a Null rather than a 0; anyone know how I can force it to see it as a 0 instead?

Here's the query I'm using:

SELECT tblCateg.sCatDesc, Count(Ratings.IN_Category) AS CountOfIN_Category
FROM tblCateg LEFT JOIN Ratings ON tblCateg.sCatDesc = Ratings.IN_Category
WHERE (((Ratings.RatingDT) Between #1/1/2007# And #3/31/2007#))
GROUP BY tblCateg.sCatDesc;