I've been a good little webmaster and tried to build backlinks by link exchanges with sites of a similar nature. My site is a city guide to an obscure place in China. I create useful, quality content, as a matter of fact, no other content like mine exists in English on the entire internet. I'm interested in google rank - generating traffic doesn't really matter. I'm stuck at #4 on google, and need to get higher.

I've been doing link exchanges with China travel sites, one tiresome website after another. Half of them don't even bother to reply to emails. When I finally get my link on their site, it's not on the front page, and some of these pages have PR0. I noticed many of the interior pages of my own website are also PR0. For example, click on "Nightlife" and examine the pages of clubs/bars.

My question: how useful is it to have these incoming links on interior pages?

Well........if your site is new one so its hard to get links for it through link exchange but if you have really good site then you will get positive responses too that will benefit you. if your incoming links from 0 PR, its not bad as if these links from really good sites then it may benefit your site as most probably they will get PR in next updation so concentrate on getting links from relevant sites.