This is the official route map, announced in Paris last October. Highlights for 2010 include:
1. Something like 13 km of cobblestone riding (Belgium and northern France).
2. Le Tourmalet (first climbed 100 years ago) will be climbed twice, including one stage finish.
3. Lots of intermediate mountain riding (Jura, Cevennes).
4. No team time trial, which should even out the field somewhat.
For more info, click on the map for the official Tour de France site.