BioConvert is a simple Python package that provides a executable that helps to make conversion between biological formats. For now, only SIF format conversion to NET format are available (see Which format can be converted ?).
The executable is called bioconvert. Type:
for more details
BioConvert is available on Pypi. Just type:
easy_install -U bioconvert
You can also use bioconvert from the Python command line. See some of the following links for example and more details about the formats.