Writting a "search engine" for a pgsql DB

Hi all,

I am asking in this list because, at the end of the day, this is a
performance question.

I am looking at writing a search engine of sorts for my database. I
have only ever written very simple search engines before which amounted
to not much more that the query string being used with ILIKE on a pile
of columns. This was pretty rudimentary and didn't offer anything like
relevance sorting and such (I'd sort by result name, age or whatnot).

So I am hoping some of you guys and gals might be able to point me
towards some resources or offer some tips or gotcha's before I get
started on this. I'd really like to come up with a more intelligent
search engine that doesn't take two minutes to return results. :) I
know, in the end good indexes and underlying hardware will be important,
but a sane as possible query structure helps to start with.

Thanks all!!

Madison