The best -- and most convincing -- source that recommends behavioral change as a remedy for snoring is SleepEducation.com, which posts information to this effect from the Clinical Practice Review Committee of the American Academy of Sleep Medicine.
According to doctors and sleep specialists, there are three main behavioral changes you can make in order to stop (or lessen) chronic snoring: losing weight, stopping smoking and avoiding alcohol close to bedtime. These lifestyle changes are more effective than over-the-counter stop-snoring products (which generally don't work or have only a mild effect on snoring), and they're less expensive and less disruptive than invasive procedures like surgery or oral appliances. If you must, a good over-the-counter choice to accompany your behavioral change is Breathe-Right Nasal Strips (*est. $6 for box of 12), one of the few OTC snoring remedies that has been shown to work (though only for some snorers).
In this article, the Clinical Practice Review Committee of the American Academy of Sleep Medicine reviews various snoring remedies. Continuous Positive Airway Pressure (CPAP) is recommended for patients who snore because of sleep apnea; other suggestions include surgery, oral appliances and behavioral changes such as weight loss.
Review: Snoring & Sleep Apnea Cures, Editors of SleepEducation.com, Apr. 2005