bp is a freely licensed perl package for manipulating and accessing bibliographic information. It supports bibtex, refer, endnote, procite, inspec, medline and other formats for input/output/conversion. I emailed the author as the bp homepage [1] does not seemed to have changed in two years... will post any response as a comment.
Links:
[1] http://www.ecst.csuchico.edu/~jacobsd/bib/bp/index.html