There are a bunch of free patterns available at this site: http://www.knittingpatterncentral.com/directory/pets.php
And here's a website that lets you plug in your dog's individual measurements and the gauge of your yarn & needles and then cranks out a pattern customized to fit your dog: http://www.thedietdiary.com/cgi-bin/chart_dog.pl
And here's a website that lets you plug in your dog's individual measurements and the gauge of your yarn & needles and then cranks out a pattern customized to fit your dog: http://www.thedietdiary.com/cgi-bin/chart_dog.pl