Poisson Solvers

PFFT

http://www-user.tu-chemnitz.de/~mpip

BigDFT

http://www.bogdft.org

Parallel FFT Package

http://www.sandia.gov/~sjplimp/docs/fft/README.html

P3DFFT

http://www.sdsc.edu/us/resources/p3dfft/

http://code.google.com/p/p3dfft