I believe the majority of senators would be more inclined to listen to constituents who snail mail in comments and concerns. I'm not positive, but I also believe faxes create more impact than emails. Politicians likely pass these faxes and letters around to shore up their positions or to assess the impact their policies make.

Does anyone know of software (preferably freeware or trialware) that will send faxes through your email program? It should be capable of sending the same fax to multiple recipients.
I've looked myself, but those I've found are either expensive or only allow a few trial faxes to be sent.
If you know of a good program please post the url.