How to create a free shipping for products in a specific category?

I wanted to create a free shipping special for a specific category, but there appears to be no place to accomplish this.   While I can set a free shipping for each product (over 1000), it would take days to do this manually, then have to manually undo the changes when the special is over!  
Can someone suggest a plug-in that can achieve this?

This will work for me (just not for the client - I could take their money every week when they want a special run, but I'd rather code than run queries all day)

UPDATE Product
SET IsFreeShipping=1 FROM            Category INNER JOIN
                         Product_Category_Mapping ON Category.Id = Product_Category_Mapping.CategoryId INNER JOIN
                         Product ON Product_Category_Mapping.ProductId = Product.Id
WHERE        (Product.Published = 1) AND (Product.Deleted = 0) AND (Category.Published = 1) AND (Category.Deleted = 0) AND (Category.Name = N'Specials')

You can achieve this by discount on shipping and discount rule. Follow below steps:

1. Create Assigned to shipping discount type.
2. Enter discount amount or percentage.
3. Add a discount rule, which will validate the discount when specific category products are added into the cart.

RE: .... a free shipping special for a specific category

You need to consider when the cart contains multiple products.  Does the whole cart ship free if it contains ANY items in specific category?   Marking products as 'free shipping' means those products won't be passed on the he shipping rate calculation, so their Weight and Amount won't affect the ByWeight or ByTotal rate calculations.

Using "Assigned to shipping discount type" will not work when there are multiple items in the cart and you only want free ship for specific items.

Also, consider that if you are offering different shipping methods (e.g. Economy, Priority), that you may only want the Economy shipping to be free (or adjusted if cart has multiple categories).