The MIT license is fine with me. I just put it in with the code files. So you are now welcome to modify and redistribute as you wish under that license.
Eric
But in the case of FFTease, you could release it under a MIT or BSD license, both of which let anyone do anything with it with minor restrictions: both require that the copyright notice is always distributed with any software that uses the code, and the BSD license requires that you get written permission before using the name of the software/copyright owner. Both of these are completely compatible with the GPL. You could also put it in the public domain, then anyone could do anything with it, regardless.