Real time radiation readings around Fukushima Prefecture can be found on NRA’s website here.
A couple of the cities near the plant have no stations but there is a wide variety around the region.
We have found many of these to be over the .5 uSv/h level used for evacuation at Chernobyl.
NRA’s radiation database can be accessed here http://radioactivity.nsr.go.jp/map/ja/download.html
SPEEDI radiation data for various locations around Japan can be found here.
SPEEDI historical data can be downloaded for locations and date ranges here. Downloads view in Excel and possibly Google Spreadsheet.
Prefecture Radiation Monitoring:
Fukushima Radiation Readings Website http://fukushima-radioactivity.jp/org-mapsearch.php
Fukushima Prefecture – This live map shows radiation levels around Fukushima Prefecture and is supplied by the Fukushima Prefecture Government.
Miyagi Prefecture radiation monitoring
Hokkaido Prefecture radiation monitoring
IIJD compiles radiation readings from a variety of sources, updated frequently usually within 24 hours or less
Safecast has citizen produced coordinated radiation readings for Japan.
Radiation Network has a limited number of sensors in Japan