Hi Pinoybroker,
Google has recently changed some of their rules around links...
Traditionally, the more links to you the better - and the more links to and from high PR sites the better...
However, in an effort to guide users to sites and information relavent to their search terms - google is attempting to classify links according to relavence to content... Therefore linking with sites that share similar content to your site, as well as good PR's will assist your site more the non-related links - which, under the "new" system will actually decrease your ranking (at least in theory).
Hope this helps...