Altered brain states
As mentioned above, applying a stimulus to the brain will eventually bring the brain's state closer to the stimulus frequency. The following paragraphs describe some possible effects of this.
Note, however, that just passively listening to binaural beats does not necessarily alter your state of consciousness. For example, willingness and ability to relax and focus attention affects how effective the binaural beat stimulus is for inducing state changes.
Helping in meditation
Meditation is essentially about willingly being able to alter one's brain frequency to a desired state. While meditators have traditionally used several years to learn the techniques of meditation, you can now attain the same effect with brainwave entrainment. No special training or great discipline is required. Good meditation frequencies are in the alpha range, from 8Hz to 13Hz.
When a certain brainwave state is experienced and practiced over a period of time, the brain will "learn" the state change and it will become easier to self-produce the desired brainwave state at will. Thus, using brainwave entrainment, you can expect to get some of its effects later even without any entrainment.
Reducing learning time
The theta stage (4hz - 7Hz) has been found to increase learning capabilities. In fact, children spend more time in theta stage than adults, which probably explains the accelerated learning capabilities of children.
Alpha frequencies are also useful for learning purposes. You can play language cassettes, subliminal tapes, etc. during an entrainment session for a maximum effect.
Reducing sleep needs
Some people have found that half an hour a day of the Theta stage can replace up to 4 hours of sleep.
Treatment of certain mental diseases
Brainwave entrainment is used in treatment of depression, low self-esteem, attention deficit disorder, drug and alcohol addiction and autism, to name a few.
Brainwave entrainment has also been found helpful in alleviating headaches and migraines.
Miscellaneous
Some users have also reported increases in their sex drive as a result of brainwave entrainment.