Ah, but to put things into perspective, take a look at this graph:
http://members.arstechnica.com/x/hux/tsunami_relief.gif
Compared to other first-world nations, Americans have been somewhat stingy.
And also realize that US citizens donated over ten times as much in the wake of September 11th, an event that -- while incredibly tragic -- pales in comparison to the utter devastation in SE Asia now.