http://forumserver.twoplustwo.com/17...llsnl-1168186/
Start there. I recommend checking out Percula's thread under the random section. It's titled recommended reading list.
If you have questions about bankroll or win rates please go to the bankroll thread.
As far as anyone being able to pick up a book and be a winning player, that's plain wrong. It takes much more than that and often times concepts or not applied correctly.
Your friends making 25-30hr at 2/5 are making a pretty good earning. The 40-50hr guys are generally running real hot or are in the top 5% at that level in terms of skill. That's a huge winrate and is hard to get to (especially the higher end of that scale - 50).