What I have learned nowadays is that you can't read the simple language of the Constitution to try and decide what is Constitutional or what is not. You'd be best off writing a letter to Sandra Day O'Connor to ask, since she's the one who mostly makes that decision nowadays.
As for my personal opinion, I think that foreign aid is actually somewhat more of a valid Constitutional power for the federal government than a lot of the domestic stuff they do nowadays, since it involves relations with other nations, which is a federal government function. But Sandra doesn't care what I think.
Well, by giving foreign countries aid, they become somewhat dependent upon us.
It keeps them in line.
hort answer? No, it isn't.