I created a DasBlog Content filter for creating Wikipedia links.  DasBlog Content filters are simple search and replace items.  It does stuff like replace ; -) with  <img alt="; -)" src="smilies/wink.gif">   (I inserted a space after ; so it would not get performed)  It can also do RegEx patterns as used in this example.

I created a derivative of their Google search that searches Wikipedia instead.  The Find Pattern is

\$w\((?<expr>[\w\s\d]+)\)

RegEx patterns. 

<a href="http://en.wikipedia.org/wiki/Special:Search?search=${expr}">${expr}</a>

This allows you to type $ w(Microsoft)  and it will create Microsoft.   (I inserted a space after $ so it would not get performed)

The imbedded HTML is:

<a href=”http://en.wikipedia.org/wiki/Special:Search?search=Microsoft”>Microsoft</a>

Multi Word with spaces works great too.  If you want it to go to a page it must be exact and unique.