CTAN has a new package: Get package/file date
The package enables to fetch dates of used packages and files and provide such information in macros. It is useful for automatic obtaining the date of a package being documented, mainly if you do not use doc/docstrip.
This package is located at http://tug.ctan.org/tex-archive/macros/latex/contrib/zwgetfdate . More information is at http://tug.ctan.org/pkg/zwgetfdate (if the package is new it may take a day for that information to appear). We are supported by the TeX Users Group http://www.tug.org . Please join a users group; see http://www.tug.org/usergroups.html .
zwgetfdate – Get package or file date
The package can fetch the date declaration of packages and files used by a document, and then provide the information in macros. The facilities provide a means of obtaining the date of a package being documented; this is mainly of use when doc/docstrip.