We wrote a very simple plugin that supports the MediaWiki-style of links to pages: Using [[Some Page]] you can reference pages in your wiki installation (or in wikipedia) directly from your issue descriptions. This is quite useful if you have issues of complex features where you need to collect a lot of information about requirements etc.
The base URL of the wiki can be configured.
Download: MediaWikiLinks-V4009-2010-09-28
Installation: Extract the zipped files into the “plugins” directory of your mantis installation and use the Manage-Plugins page to install and configure.