I've used the ZoneInfo (PublicDomain.ZoneInfo) project from CodePlex for quite a few years, especially in Catfood Earth. The project had rusted a little so I emailed the author (Mark Rodrigues) and he was kind enough to add me as a developer. I've just updated ZoneInfo with some of the local changes I'd made and a variety of patches from the CodePlex community. It now works with the latest IANA tzdata file, at least for the test cases I can run. Let me know if I missed something (and thanks Mark for letting me contribute back to this very helpful project).