One of my collection of handy tools playing with PDB data format is convpdb from Scripps. It can do:
Ray asked me how to get the sequence of the PDB and get the one-letter codes in the dumbest way.
It turns out this fortran program can do the magic http://www.ccp4.ac.uk/dist/src/pdbset.f. My way is kinda crap, I use RasMol's 'show sequence' and paste the sequence to those web service. ^^;