Definitely not for me. I've spent the good part of two and a half years growing my mane, and it's become attached to me. I can't see myself ever having short hair again. I think long hair is incredibly masculine, provides a lovely blanket of warmth in winter, and can make *some* girls go nuts.
I think there are much more productive ways of raising money for charity. And I find it ever so slightly sexist that the majority of females who support such an act of "charity" encourage and in some cases I've witnessed, actively push males into giving up their locks, but would never dream of giving up their own hair. I don't buy the whole "but I'd look stupid, you wouldn't" argument. Girls have told me I should do this in the past. One even said I was selfish, as boys are "supposed" to have short hair anyway. Girls only think they'd look silly as it's ingrained into the mindset of the majority of society that girls are "supposed to have long hair".