Some useful ultra running links:

www.ultramarathonrunning.com   A comprehensive world ultra guide.

www.beyondmarathon.com   World wide ultras

www.rorycoleman.co.uk   Some excellent UK ultras

www.100marathonclub.org.uk   Marathon listings UK and overseas

www.multidays.com   Listings of world ultras

www.gobeyondultra.co.uk   A great selection of UK ultras

www.badwaterbenjones.com   Badwater stats since race began, including doubles, triples, quads!