This tutorial by Tim D’Auria on Youtube, is shorter than 30 minutes. Without pretending too much background it gives you the basic tools and knowledge to build a basic document classification system. The classifier uses a simple KNN classification algorithm and text mining techniques to learn to distinguish the candidate who pronounced the speeches of the 2008’s US Presidential campaign, the two candidates being Barak Obama’s and Mitt Romney.
Best of all this is an excellent example of the R tm package in use.
Links:
A gentle introduction to text mining using R | Eight to Late
