This article is from the Bicycles FAQ, by Mike Iglesias with numerous contributions by others.
From: Name removed by request
[A summary on studded tires compiled by a reader. A complete copy of
the responses she received, including some that give directions for
making your own studded tires, is in the archive.]
Studded tires do help, especially on packed snow and ice. On fresh snow
and on water mixed with snow (i.e. slush) they're not significantly different
from unstudded knobbies.
On dry pavement they are noisy and heavy, but can be used; watch out for
cornering, which is degraded compared to unstudded tires.
Several people recommend a Mr. Tuffy or equivalent with them; one
respondent says he gets more flats with a liner than without.
In the U.S. the IRC Blizzard tires are commercially available. They
can also be made.