Unicycling Org: an official reference website for all related topics
Unicycletips.com: Plenty of tips and advice about unicycle in general.
International Unicycling Federation : with competition rules, events dates etc...
Unicyclist.com an official source of information for events, competitions and a forum.
The unicyclist Forum: one of the best forums on the topic.
Huge photo gallery from the Unicyclist.com website.
Unitours: organisers of unicycle touring around the world.
Unicycle TV: an excellent source of streaming videos, with channels covering competitions, crashes, conventions etc...
Syko Production: plenty of media around unicycles, photos, videos
Kris Holm: One of the pioneers in unicycle trials, probably the Ryan Leech of unicycle.
Xavier Collos: A French champion and World champion in unitrials and freestyle.
Patrick Schwartz's website with plenty of tips (in french)
Toronto Unicyclists: A cool site made in Canada
Learning unicycling: an excellent starter to read in pdf.
Syko webmaster's personal website. A cool obsession about unicycles.
Monociclos: for the Spanish community.
Fédération Française de Monocycles: the FFM page with official french rules and events
Schlumpf Drive: a German manufacturer that makes multiple gear unicycles!
The Ultimate Wheel: what is it? See how to build one and ride it
Unicycle.net: an good site for generic unicycling tutorials.
Where to buy Unicycle components?
Unicycle Shop with plenty of products and info.
Municycle: a huge shop with all the brands worldwide.
Kris Holm's catalogue of unicycle components.
Koxx One an excellent reference site from Koxx
Qu-Ax: A German manufacturer, from unicycles to pogosticks!
Monociclos: una tienda para los monociclistas hispanicos.
Kahero: Un magasin bien sympathique sur Brest.
Semicycle: a cool shop for circus activities and equipment
Some cool unitrial videos to get inspired
Just click on the films, for streaming video directly online (approx 30s loading time).
You can also download most of these .wmv files from TV ISG.
Also check out some interesting videos posted on YouTube.