Forum plugin ( change word to link) ?

[xgnux]

Hi,
i saw this on pay per install forum and some other forums.
i am searching a plugin that will convert pre defined words to a link...

for example if someone writes "hostgator is a great hoster" its should replace the Text Hostgator with a Link to Hostgator and Anchor Text Hostgator.

Anyone knows a Plugin which does this ?

greetings Gnu