iPhone Email - How to prevent a datestamp from being turned into a Link to Create an Event
From my experience no, 

Apple is just trying to make your life and the recipients lives easier by using microformats, an in this case the hCalendar version so that they can be understood by other programs {like a calendar app}.

see:

http://microformats.org/wiki/hcalendar for a full explanation of the format.

The only way-tat i know of-to solve this would be to jailbreak your iphone and change the style of the formatting [or remove the format altogether].

There is an issue with microformats that you may want to consider if you email blind people, see:

http://www.bbc.co.uk/blogs/bbcinternet/2008/06/removing_microformats.html

I know that this does not explicitly tell you how to sort this yourself, but I hope that with this knowledge you may just overlook the bad style in favour of the time savings that the hCalendar offers you and others.