Brauns Online
Sells 20' and 24' standard unicycles as well as 5' giraffes.
http://brauns.com/

Infinite Illusions, the Unicycle Store
Makes and markets a variety of specialty unicycles, juggling equipment, yo-yos, tops, and other skill toys. Also, offers videos, books and parts for the enthusiast. Offers online, mail order, fax and phone ordering for domestic and international clients. Based in Tallahassee, Florida.
http://www.infiniteillusions.com/

MYS Corporation
The distributer of the Miyata unicycles and mountain unicycles. Products made in Japan with pricing in Japanese Yen. [English / Japanese]
http://www.mys-co.com/

Norco Performance Bikes
20' and 24' unicycle
http://www.norco.com/firstscreen.htm

Rideable Bicycle Replicas
They sell big-wheel unicycles as an offshoot of the Penny-Farthing bicycles that they make.
http://www.hiwheel.com

The UK's Unicycle Source
Unicycle Source web site selling unicycle online to the UK.
http://www.unicycle.uk.com/

Unicycle Club
Sells unicycles and accessories. Includes tips on how to add a club to your school physical education program.
http://www.unicycleclub.com/

Unicycle Source
A mail order company in the USA that sells unicycles and other unicycling related merchandise.
http://www.unicyclesource.com/