A guy I work with showed me this site yesterday: microsievert.net
Best to look at the animation on the live site then use the screenshot below for a basic translation.
A brilliantly simple way to represent all these numbers being thrown at us everywhere we look, even at the end of the weather forecast.
The top row starts with the worldwide normal average on the left, increasing up to RUN AWAY! on the right. The bottom two rows show the actual current readings at main cities in the various prefectures in East Japan including at the exclusion limit around the reactor. I live closer to Shinjuku than Chigasaki, but between those two.
I've checked the data against a few other sources and everything seems to tie up. No need to divide some obscure number by the number of hours in a year any more, or convert micros to millis, just check it's still only pitter-pattering between here and Fukushima... and run to the hills if it starts snowing.
Currently drier than average though.