Postural change as a remedy for snoring is more anecdotal than scientific, and a representative anecdote (which is backed up by posts from other snorers) comes from Slate.com's Chip Brantley, who says he got the best results by taping a tennis ball to his back.
Sleeping on one's back is a primary cause of ordinary, non-sleep-apnea-associated snoring, medical experts say. One reviewer for Slate magazine, who tried out a variety of snoring remedies, says he stopped snoring when he taped a tennis ball to the back of his T-shirt, an approach that's backed up by anecdotal postings on online bulletin boards. Keep in mind that this is not an appropriate treatment for sleep apea, but it may be a technique worth exploring before you invest in a dubiously effective OTC remedy like Breathe Right Nasal Strips (*est. $6 for box of 12).
Brantley describes his experience with a variety of stop-snoring products, rating them for ease of use, restfulness when waking, and his wife's irritation level. He says he gets the best results from a tennis ball taped to the back of his t-shirt, and gives the runner-up spot (facetiously) to the $45 Anti-Snor Therapeutic Ring.
Review: Silent Night: Which Snoring Remedies Actually Work?, Chip Brantley, Sep. 20, 2007