What sort of search engine do you want? A full text? Image or something more specific?
I have a search engine which isn't reliant on google and have numerous pages.
1) A crawler - this opens up URL's and searches for <img> tags and then saves to an index which can be searched using fulltext.
2) A URL queue - the crawler is split into twp parts - a content search and a URL search. If all content is exhausted, it will go to the next available URL in the queue.
3) A search page - pretty basic - searches through the index.
4) A URL check - a page that continuously loops through the index to ensure they are still there and that the content is the same.
5) A few other maintenace pages...
It depends on what you want to achieve. Don't ever expect to get to the standard of google or any other major search engine becuase you just wont have the processing power. Try to get a Unique feature in that really appeals.