This year Boston compiled a highly detailed cycling safety report that includes location data for accidents, and a lot more:

PDF warning

http://www.cityofboston.gov/images_documents/Crash Report 2013 FINAL reduced 2_tcm3-38304.pdf

Appendix B contains a review of other cities' collision reports.

edit: HN fails with spaces in the URL. The link to the PDF can be found on http://www.cityofboston.gov/bikes/bikesafety/ .