Firefox, IE7+ and Chrome support this, just click to install it. (opera users, please kick Opera in the rear

https://addons.mozilla.org/en-US/firefox/addon/155820
(It's still pending review by the AMO staff, but you can use it now by checking the "Let me install this experimental add-on".)
The cool part of the site specific search as done by this plugin is that you will not see site: in the search field of Google,
and you can enter new search criteria in the result page and you will still remains searching within the forum.
As the search-as-you-type is also site specific it will only suggest common words that are found in this forum rather than the entire world.
(not entirely sure how Google maintains this but I assume if more people use this plugin, the suggestions will improve over time as well as Google will auto-update it's word look-up database)
I'll make sure to keep this updated in case any tweaks are needed in the future.
PS! Fred, Freak, if either of you guys have registered at https://addons.mozilla.org/ then please email/msg me (via this forum) with the url to your "about" page at AMO so I can add you as Creator/Developer of this plugin too. I created the plugin but it's kinda the PureBasic community's really so it's only fair that you are able to maintain it's source as well.