As I can't find a calendar file to download for the RBS Six Nations 2010, I've made one myself that you are welcome to use.
It's available in several formats:
vCalendar file (.vcs)
Comma Separated Variable(.csv)
Zip file of Time & Chaos Transportable Records (.ixl)
The start times are all shown as Greenwich Mean Time. Where a separate KO time is shown, this is the local time for matches in Paris and Rome only.
Looking forward to a great tournament, but Stade de France on a (cold?) March night could be a very tough place for England to finish their campaign.