They're not all smooth, Pooks, but I think you'd like smooth ones if you're riding mostly pavement rather than dirt. I've taken my bike on really hard packed dirt roads since putting the slick tires on it, but I tend to ride more slowly, since there's less traction!
Armadillos are made by -- or marketed by -- the Specialized bike people, so look for a Specialized bike dealer, and you'll probably find them!
Karen in Boise