Most of these websites give some brief explanation of entrainment. The example you hear most often is that of Dutch polymath Christiaan Huygens, who in 1665, hung two pendulum clocks next to each other on a wall. He noticed that the pendulums eventually matched each others' frequency, but always in antiphase, opposite to each other, as if canceling each other out. He'd try disturbing one or setting them in sync, but they'd always return to the same antiphase synchronization. Huygen's experience is widely touted on binaural beat websites as a demonstration of how systems can become spiritually connected through some energy field. However, they misunderstand what happened, and have not read the full story. Huygens also tried taking one clock off the wall, and as soon as they were no longer physically connected to one another via the actual wall, the effect disappeared. It was not the proximity of the clocks to one another that created the entrainment; it was their physical, mechanical connection to one another. As each pendulum swung it imparted an infinitesimal equal and opposite reaction to the wall itself. With two clocks on the wall, the system naturally sought the lowest energy level, according to the laws of thermodynamics; and both pendulums would thus swing exactly counter to each other, minimizing the system's total energy.

Joseph Kao, creator of Profound Releasing, Profound Renewal, and Sound Asleep, is a hypnotherapist and a solution-focused therapist with a private practice in Cambridge, UK. Joe was the co-developer of an acclaimed course on conversational hypnosis, and he regularly teaches hypnotherapy and psychotherapy to other therapists. He has also been the head scriptwriter for over 800 professional hypnotherapy recordings. Joe was drawn to the world of philosophy, meditation, and brainwave entrainment technology from an early age, and he’s had a daily meditation practice since 1998.
Although getting organized and staying organized is not often thought of as a stress management technique per se, this is an activity that can reduce the stress you face in your life, and can even be calming as you are engaged in the act. (See how cleaning can be a stress reliever in itself.) By working through the clutter of your life, you can eliminate those energy drains that can make you feel like you're 'being pecked to death by ducks' and reserve that energy for dealing with life's more important challenges. Read more on being organized and eliminating extra stress from your life. 
Absolutely. Binaural beats were first discovered over 150 years ago, and their use in brainwave entrainment audio has been the subject of a great deal of scientific exploration over the last 35 years in particular. Millions of people use brainwave entrainment music to enhance their quality of life and to experience deep relaxation. In fact, brainwave entrainment technology is now used for more than just meditation. It is also used by a variety of practitioners and private users for improving self-confidence, stress relief, pain management, relaxation, improving and concentration and improving the quality of one's sleep. If you would like to read an objective third party report on binaural beats, please refer to this Wikipedia article.
It should be stated that if we are listening to LifeFlow and we are intentionally seeking to enter into meditation, the chances are good that we will do exactly that rather than just being in a daydream or some other pleasant state. It’s no guarantee, but the combination of meditation and brainwave entrainment raises the odds that we will accomplish our meditative goal.

When you're having a hell of a day—good or bad—checking out for 10-15 minutes is revitalizing. Find a place where you can be alone (and definitely ditch the cell phone)—the attic, the bathroom, a quiet cafe, a big oak tree—and wipe the slate clean for a few minutes. Do whatever it is that relaxes you: Meditate, read a novel, sing or sip tea. It's crucial to take just a few minutes everyday to de-stress. It's not how much time you allot, but being consistent that's important.

In 1956, the famous neuroscientist W. Gray Walter published the results of studying thousands of test subjects using photic stimulation, showing their change in mental and emotional states. He also learned that photic stimulation not only altered brainwaves, but that these changes were occurring in areas of the brain outside of vision. In Walter’s words:

The functional role of neural oscillations is still not fully understood;[6] however they have been shown to correlate with emotional responses, motor control, and a number of cognitive functions including information transfer, perception, and memory.[7][8][9] Specifically, neural oscillations, in particular theta activity, are extensively linked to memory function, and coupling between theta and gamma activity is considered to be vital for memory functions, including episodic memory.[10][11][12]