Most of what I know about value investing comes from Warren Buffett's article The Superinvestors of Graham-and Doddsville,which is based on his speech at Columbia Business School in May of 1984, celebrating 50th anniversary of publication of Security Analysis by Graham and Dodd. ( I have a PDF version of it, but don't know how to upload it, for those who're interested, i can e-mail it to them).
The message is rather simple: find the undervalued (by the market) securities, and buy them.Then sell those that are overvalued. He shows the track record of many students of Graham ( like himself), which speaks for itself: most of them beat S&P 500 returns by 60-80% annually, on average. The point Buffett is making is that all these people are buying the business, not its stock.
You just have to find those undervalued but strong businesses, and profit from it.
Some authors (for instance, Burton Malkiel in his A Random Walk Down Wall Street) argue, however, that the information investors( even the professional ones) have to evaluate businesses is far from accurate and include "creative" accounting and other gimmicks to inflate the stated earnings. ( memories of Enron are too fresh in our minds...)
However, Buffett has his record- can't argue with the facts.