phranque - 12:20 pm on Feb 10, 2012 (gmt 0)

part of the solution is to redirect with a HTTP response using a 301 status code and a Location: header.
like this:

GET http://www.example.com/bookingform.php?property=nameofproperty 301 Moved Permanently Location: http://www.example.com/nameofproperty.php

assuming your server is apache you can use mod_rewrite to look for these patterns with regular expressions and RewriteCond/RewriteRule directives.
you should even be able to find examples of rewriting parameter values to php files in the apache forum on WebmasterWorld.

the other part of the solution is to refer to the canonical url from the booking form.

if you use the disallow in robots.txt the search engine will never see the redirect to the canonical url and the non-canonical url will likely get indexed without a snippet.