I am trying to get valuable links for my page. And I read about PageRank here at webmasterworld. I understand that I should check the PR of a page, before contacting them for a link. The better PR, the better for my page. Right? But... eh... do I have to check the PR of the main page or the PR of the links page? And what will happen if I (PR 4/10) cross-link with a site with a lower PR (e.g. 1/10)?
I wouldn't be too concerned about PageRank, other than avoiding pitfalls like linking to bad neighborhoods.
Even if a PR1 is good, and sometimes PR0. PageRank is a relative thing and chnages over time. Therefore a new site linking to you may have very low PageRank today, but that can change dramatically over a year.
The best direction to head in (and to save time) if sites are current in Google now - they are likely good to link to & receive links from, thus search for link exchnages in Google and leave PageRank to develop on it's own.
You will want to look at the actual page that is linking to you.
Also, don't let pagerank influence your descision too much. The site could be new and still building it's own pagerank. Take a look at the structure of their site and their links page. If you feel that the links page is burried too deep in the site and will never gain better rank, then look for another link partner.
Just remember, the links are supposed to be there for your users. If you feel the site is useful to your users, then give them what they are looking for.