If you haven’t already checked it out, check out the Fastnet race tracker. I always find these a little clunky but this one’s fairly easy to use. One word of warning it seems to explode my Firefox browser. Not ideal!
Also check out Nick Jaffe’s BigOceans blog and his neat little tracker. Nick is single-handeding his way back from the Netherlands home to Australia. He has a neat little Google map thing to track his course. It seems to tied in to his Twitter feed broadcast through Iridium. 
OK, Nerd Alert!
Hey Adam,
I thought I would double-nerd your post with some info about my new tracker… It is Flash application fed with GeoXML, that includes my geo-referenced Flickr photos (clicking the white icons brings those up) and a GeoXML export of my positions, which have been maintained throughout my trip since Holland.
I update my position over Iridium using email, which then cross-posts my message to Twitter. I’ve just added stats to my updates too, which will include speed over ground, heading, 24 hour run, miles to destination etc… Which will also be updated to Twitter when I start my next leg (waiting on Hurricanes here in Honolulu…). My tracker is part of a bigger project.
As I am a bit of a tracking geek, I might add that the Rolex tracker is written by Geovoile, a French company. Their race tracker is in a lot of big European racing, including the recent Portimao Ocean Race (http://www.globalracetracker.com/en/). One of the neat things about their tracker is the weather/GRIB overlay. 😉
Ok, no more nerding.
Cheers, Nick