Dear Funetical,
To me it comes down to making a choice about charities that directly support cycling or charities that are supported by cycling (e.g. Cancer research via Armstrong) .
As I live in Melbourne Australia I can't offer much regards the US scene however the idea of this charity in the US
3 Feet Please-Saving cyclists' lives
has now been picked up by a foundation set up here to research cycling saftey following the death of a well know Australian cyclist in Germany (The world is certainly getting smaller)
a meter matters
Another option is to see if any Universities in your area engage in road saftey research and donate towards any studies they do regarding cyclist safety
Cheers from Downunder
Cy(cle)borg