I can't say anything positive about the Secular Student Alliance. They are clearly not worthy of support.
Free speech, however, is worthy of support. Unfortunately some people seem to disagree with it. Recently, the SSA has been targeted by Distributed Denial of Service attacks. One of their employees reports that they have meanwhile installed effective defenses, but those cost money. I think it is reasonable for Christians to donate towards offsetting that cost so as to make clear we don't approve of that kind of crime for which could easily have been committed by overzealous idiotic coreligionists. Basically it's not about supporting them but about restoring the status quo ante.
To that end Adam Lee of Daylight Atheism is collecting money from Christians who would like to contribute without giving our contact info to the SSA. I think he can be trusted in that regard. I've embedded his chip in widget at the top of this blog's sidebar (to the right) and I encourage you to contribute as I did.