XKCD did a guide to converting to metric here:
xkcd - A webcomic of romance, sarcasm, math, and language - By Randall Munroe
(Slightly off-color humor, but I think he's right in that to successfully convert to Metric, Americans need to 'think in Metric,' not just try to convert on-the-fly.)
On the subject, I was amused (confused?) to learn, when I weighed myself on a scale at the exercise room in a London hotel last year, that I weighed 11.5 "stone"....
