Population genetics in Biopython
Code pertaining population genetics in Bipython can be found in the PopGen module. Most documentation can be found on the PopGen Chapter in the Tutorial (PDF).
Currently, most code available wraps existing functionality provided by external programs, namely SimCoal2 for coalescent simulation and fdist for Fst based selection detection.
Python programmers might want to consider PyPop which includes intra-population frequentist statistics and simuPOP for foward-time population genetics.
Any notes (or discussion) about possible future developments should be restricted to the PopGen development page.