SpreadsheetTo is a python library and command line utility for turning spreadsheets into text and programmer friendly formats.
It supports xls and xlsx on the input side, and CSV on the output side, with more to come on the output side.
This library began because so many open data projects seem to start by parsing Excel spreadsheets into something else, and all of my projects had an ad hoc implementation of that using a library that only worked with one version of Excel documents.
This library only supports Excel for now because I haven't yet seen any other spreadsheet formats while browsing data.gov for interesting datasets. That can always change, though.