Do you use Chrome? You can list this search engine as a custom search engine in Preferences > Basics > Manage Search Engines...

Add a new search engine -> Hacker News

Keyword -> hn

Url with %s in place of query -> http://www.hnsearch.com/search#request/all&q=%s

You can do the same thing with a keyword bookmark in Firefox.

I've been searching HN all this time with a custom Google search including "site:news.ycombinator.com". I'll have to see if this is better. Google offers results filtered by date, which is really nice, since technology moves so incredibly fast.