There is 4 momsclasses in Sweden (25%, 12%, 6% and 0%).

Under Sales-Tax-Manage tax zones & rates:

Create one rule per momsclass for Sweden with * as region and * as Zip.

Create one rule for customers.

Create one rules per momsclass for products.

Create one Tax rule for each momsclass.

Make sure that the products in the catalog have tax set (if there are product in the catalog).

Under System-Config-Tax make the appropriate settings. (defines if the prices are including or excluding tax, if tax should be added on shipping or not etc)