How to extract appointments (dates and times) from e-mail text

A friend of mine gets appointment requests in e-mails but cannot control the format (.txt, .html, .rtf, etc.) of them nor the layout. He would like his Outlook to create appointments for him based on the date and time information included 开发者_如何学编程in the message bodies. Smart Tags does not do this for him as well as Mail.app for Mac does. What can he do? I was about to write a short VBA script for him that would parse his text selection and create a calendar entry but then realised "date and time parsing" including time zone detection must be a problem that somebody has already solved. Is there a de facto standard library for this? How would you go about coding something like this? Could one just download a ready-made solution?

I could in fact not find a "de facto" standard library for this.