Opinion Mining Training Data

I've started to scratch the iceberg with Machine Learning because I'm fascinated with the idea of distinguishing the subjective and objective elements of texts.

This article: http://dmlab.uos.ac.kr/html/lecture/DataMining(2009-1)/Determining%20Term%20Subjectivity%20and%20Term%20Orientation%20for%20Opinion%20Mining.pdf discusses the possibility of "opinion mining" using data sets of labelled subjectively positive and negative examples. Maybe I'm fumbling on describing the paper, it's probably because I can barely understand what its going on about.

I guess I have a couple questions that someone who can understand the article/topic could answer for me.

1. What prerequisite knowledge do I need to recreate this in a functioning application.

2. How would I get the training data. (The links in the article don't seem to be working anymore.)

Free online resources are preferred, but if you have suggestion of a good paid learning resource that's cool too.