vo.conesearch is a Python package to make performing VO cone searches on popular catalogs simple.
This package uses the VO conesearch protocol (v1.03) <http://www.ivoa.net/Documents/REC/DAL/ConeSearch-20080222.html>
Some examples of simple usage follow:
import vo.conesearch as vcone
tab = vcone.conesearch('usno-a2',ra=10.2,dec=65.4,sr=0.1)
will return a numpy structured array containing the contents of the returned list of stars found in the USNO-A2 catalog.