The Poker Bank presents the easiest to follow guide you will find when it comes to No Limit Texas Hold' Em. If you are starting from zero. This is a good shortcut to jumping right in. Once you read this, you are ready!
A complete school that will take you from beginning to end. You will learn everything there is to know for Hold 'Em and Pot Limit Omaha. If you create an account, this site will keep your progress and eventually, you can even graduate.
PokerStrategy is another curriculum designed to track your progress and give you graded quizzes much like Card Player School. The look of this site is a little bit more updated and it covers a few extra things. You may like this one more, depending on your style.
Just like there are a lot book and sites that teach poker, there are A LOT of apps that focus on doing the same thing. Poker Fighter makes a game out of learning and makes it fun to practice. Also, you can use this app on your phone or computer.
Poker is something you never stop learning. Players that have been in the green for years can attest. Optima Poker Trainer is a tool that you can use to exercise and take notes with once you have learned a thing or two. This is a coach walking you through each players hand at a table so you know what to do and look for in multiple situations - from your prospective and your opponents.