This is a rather large topic and whether strength or power is of greater importance is dependant on your sport. To define it simply Maximal Strength (Fmax) is the most weight you can lift regardless of the time to complete the lift. Force is defined as F = mass x acceleration. for any object you attempt to lift, you must overcome gravity (which accelerates all objects at 9.8 m/s^2). When you train your maximal lifts you are training the maximal force – the bar moves somewhat slowly.
Power is the rate of force development. There are two equations which are used to measure Power. (1) P = Force x Velocity; and (2) P = Work / Time. These two equations actually say the same thing since Work = Force x Distance and Velocity = distance / time Therefore Force x Velocity = Work / time.
Powerlifting is somewhat of a misnomer since it is actually a test of limit strength or Fmax. Olympic lifting trains power -- or the rate of force development. In most sports, the ability to generate force rapidly is critical to success. This is one of the reasons why Olympivc lifting (or variations thereof) are so good for many sports which require a high rate of force development.
Other than the Westside Barbell Method, most powerlifting approaches do not develop Power (also referred to as speed-strength or strength-speed depending on which is more important).
An excellent resource on the internet to learn more about sports training and how to develop maximal strength and power is the drsquat site or you can join Dr. Siff’s Supertraining egroup on yahoo.
Some good books are "Power: a Scientific Approach" by Hatfield, "The Science and Practice of Stength Training" by Zatsiorsky and "Supertraining" by Siff and Verkoshansky. Bompa's Serious Strength is a good (albeit) flawed primer on the effect and methods of the different types of training.