The most prominent US humanist organizations, the Council for Secular Humanism and the American Humanist Association, have appeals for donations to help Haiti, through secular channels. (CSH site; AHA site.)
In the interests of equal opportunity cynicism, though, I have to wonder how much of this is motivated by a need to demonstrate that the nonreligious can also be charitable. (“Look, we can do this too!”) I would expect it’s part of the picture. Christians often point out the social benefits of their beliefs by saying they organize all sorts of aid to the unfortunate. Some go further, accusing nonbelievers of being less interested in helping their fellow humans. There is, in fact, some (though controversial) social science supporting this accusation. So secular humanists promoting the social respectability of nonbelief have some incentive to visibly support secular means of aid and charity.
I don’t think that means too much, one way or the other. Our motivations are complicated. I guess one might ask if secular impulses to aid would be sustainable in the absence of a need to compete with religion. That’s a very difficult question to answer. My guess is that yes, secular aid and charity has its independent motivations. But secular charity and mutual aid also has a different character than the more traditional religious variety. I imagine those of us who are religious or nonreligious generally prefer our own way of doing things, regardless of comparisons of dollar amounts and so forth.