Buds Guide To Hooking a Bowling Ball

Steps
Get the right equipment. No matter what you do, if the ball is not right, it's not going anywhere. You need a ball made of Reactive Resin or better (e.g. Particle load or newer epoxy resin coverstocks). These are very easy to find and can be bought at little expense.
Have the ball drilled correctly. This is a personal thing depending on where you bowl, so you will need to talk to your local pro-shop operator for advice on this one. The drilling for the ball is very important, if not crucial, so make sure the drilling is appropriate for the conditions you bowl on and your own physical limitations.
Grip the ball with the two middle fingers of your dominant hand (i.e. the hand you bowl with) and place your thumb in the thumb hole. For extra kick, it helps to tuck your pinky finger in under the ball, but that's a comfort thing.
Visualize the line you'll take across the lane. Depending on the lanes you bowl on, this will vary greatly, but let's focus on a typical house condition. All the oil is on the inside, leaving roughly 8-10 boards of relatively dry lane to be used. These boards can be both a friend and enemy to you. Depending on the amount of oil, you will want to line up your feet on the left hand side of the lane, generally with your right foot in line with the last dot on the approach. You then want to aim to throw your ball down the lane to the right hand side, across the lane, more or less aiming for the gutter on the right hand side (opposite for left handers). The easiest way to teach aiming is to use the arrow markings on the lane, or just just aim to throw the ball into the gutter about 3/4 of the way down the lane.
Time your release. Take four steps like this: one, two, three-four. Step three is actually a half step, called the pivot step, used to get yourself into position. While these steps happen, you need to swing the ball in time with your steps so the time you release the ball meets your ankle at ground level (or as close as you can comfortably get) at the time you are sliding. So, you want to push off the ball on your first step, and be at the top of your back swing by your second step, then bring the ball back through and release by the end of your slide, either in line with your ankle, or just behind it.
Make the swing. This is where the magic happens. Generally, before you push off, you want to hold the ball with your arm at a right angle pointing straight out in front of you. Make sure that your thumb is on top of the ball (so, your palm is facing up, underneath the ball) and angled toward 10 O'clock (or North West if you prefer to use compass references). Keep your wrist cocked and keep it that way through the entire swing. This will be important later on.
As you come through to release the ball, generate rotation on the ball, or it isn't going to hook. The most effective way is to slightly bend your elbow in the downswing and on release, straighten your elbow. As you release the ball, quickly un-cock (or break) your wrist. This creates a whipping action, or wrist snap, similar to the way you throw a Frisbee. It can generate up to 400 RPMs and for experts and pros, up to 700 RPMs, making the ball hit the pins with a massive amount of power.

Tips
When you swing the ball, it is important not to force the swing. It should be a pendulum-like action, allowing gravity to dictate the swing. Should you need more or less ball speed, hold the ball higher or lower before push-off (higher for faster, lower for slower).
Keep yourself relaxed, and for added hook in the backend, rotate your arm around the side of the ball upon release. This generates more side roll, causing the ball to "flip over" and roll aggressively toward the pocket.
Remember to pump your fist and the like when you throw your first big "coast to coast" strike.