To learn how to read piano notes it is essential to learn some basic theory. Nothing to complicated, just enough so you understand what the notes are called. This is actually easier than you might think because there are only seven notes to learn. These notes are C, D, E, F, G, A, B. These are all the white notes. The black notes are the sharps and flats and you won't even need these to start with.
There are various ways you can learn to play the piano. There are tutor books for beginners and there are piano courses that you can download to your computer. Tuition book such as "The Complete Piano Player" and "The Complete Keyboard Player" can be ordered online or at your local music shop. Piano courses are normally downloaded from music sites, which specialise in piano lessons.
Tutor books Vs piano courses
Tutor books are probably the cheapest option and it is possible to learn to play the piano with this method. However, they are really designed to be used by a piano teacher with a pupil. Unless you have some basic knowledge of music, it is possible to pick up some bad habits, which you may not be immediately aware of. A teacher would prevent this before it starts.
A piano course or piano lessons software is by far the better option. Many of these courses include audio and video files, which can literally show you how to play the piano without those nasty bad habits, which many learners can pick up without the proper direction.
Look, listen, copy and play
Most piano learning courses come bundled with lessons that will take you from beginner to advanced. The simplicity of how these courses are laid out is one of the reasons they have become so successful. The video and audio files are the key to your success. You just copy what is on the video or audio file until what you are playing matches what is being shown and that's it, move on to the next lesson. Don't expect to learn to play overnight, it's a gradual process and the piano software system is almost like having your own personal piano teacher 24/7.
Whichever method you choose, try to make your practice time a habit. If you were going to a piano teacher, you would need to practice every day. You should do the same if you intend to learn by yourself. All beginners need a minimum of half an hour per day learning and practice time, anything after that is just having fun time.