This does either... It's not too easy to skin (Trust me on that one ), but the results are pretty easy to tweak... On-Page factors only (Of course) are taken into account. http://www.xav.com/scripts/search/
Yeah, it's pretty good... Like I say, it would be nice to be able to take links into account too, but then it would get pretty complicated pretty quickly. The only other issue I have with it is the fact that you have to manually crawl the site in order to add new pages to the script. It's great with a static site, but not too great with something dynamic... The way you can tweak weighting factors is pretty cool though. I think I still have it installed somwhere - you're more than welcome to play with it.
FREE - http://www.echoarticles.com/echosearch/index.php Looks pretty comprehensive. Never has the time or need to sit down and try it though.
I've used this script http://www.isearchthenet.com/isearch/ works great. It spiders given urls and stores in in a sql database. I use it on a website to search the website.
XAV is great, I fully reccomend it, just.. keep your pages under 20k! You may wish to check hotscripts.com for more PHP\SQL along with other scripts.
Works great http://www.blogparty.net/directory/ But can it be set so that by default it goes for results from your own results rather than general Google ones?
Just set it to be only your site. Although I wasn't really talking about that one, rather the actual script you download. It's better.