The original DFprot web server for predicting main-chain deformability from a single protein conformation has been replaced by http://imods.chaconlab.org/ that includes a more robust way to performs a normal-mode analysis (in internal coordinates). In this server you can calculated from a uploaded structure its capability to deform at each of its residues. In any case, you can still download the executable to calculate the deformability based on NMA in Cartesian coordinates.
Garzón JI, J. A. Kovacs, R. Abagyan, and P. Chacón. Dfprot:A webtool for predicting local chain deformability Bioinformatics. (2007) Apr 1;23(7):901-2.