A while ago, I posted a bookmarklet called Hacker Panel that actually shows HN comments for the current page. Do check that out too!
Shameless plug: is is my last bookmarklet for HN: http://christopherdebeer.github.com/hnCommentWatcher/
Update: I was a bit let down that you just show the HN page in an iframe, nd dont actually restyle the comments in a user friendly way like in a side bar for the site (which i think would be brilliant)