Trial offer: Watch a clip free each day when you create an account at Xobile, a mobile phone download and streaming service offered by Xobile (pronounced zoh-bul). It's owned by AEBN, which also operates Rent Adult. Rental fees: $7.90 for 18 credits (44 cents each), $17.90 for 70 credits (26 cents each) or $39.90 for 230 credits (17 cents each). Each clip costs two credits for seven-days of streaming or download access. You can choose to view the clips at low, medium or high quality. The average Internet-enabled cell phone can store up to 700 clips. Number of clips: 3 of 4 stars. Technical requirements: Mobile phones that can access the Internet and have Windows Media Player, Real Player or 3GPP installed. Credit cards accepted: Visa, MasterCard, Discover, online checks, PayCash, E-passport, JCB. Privacy policy: Not posted. Customer service: 800-628-0241 or email.

Best Adult VOD Site?: The most popular VOD service in our guide is Hot Movies, which has tens of thousands of adult titles. You can buy access by the minute (at 8 cents and up) or purchase unlimited viewing of any individual title for two, seven or 30 days. Our most popular flat-rate site is Video Box, which charges $9.95 per month for unlimited downloads from its library of more than 3,000 movies.

Prefer to Rent DVDs?: If you prefer to rent DVDs rather than download movies, compare online services at our Adult DVD Rental Guide. Most charge $10 to $30 per month to have one to three adult DVDs out at a time, with no late fees or return dates. A few rent individual DVDs for $3 to $5 each per week. A credit card is required to join any DVD rental service.

Buy Adult DVDs Online: If you're looking for bargains and selection, we suggest Movies by Mail, which offers new customers a free movie when you pay $4.95 shipping, or Overstock DVD, which sells closeout adult DVDs starting at $3.99. For other adult DVD stores, including some that offer coupons for $5 to $50 off your order, see our Adult DVD Buying Guide.

Video Gold Adult DVD Club: Choose two adult DVDs for $5.95 each plus shipping when you join the Video Gold Adult DVD Club from Adam & Eve. You'll also be able to choose a third adult DVD free. As a member, you must purchase two more DVDs at regular club prices within a year. Or purchase a fourth DVD when you sign up for $19.95 and buy just one additional DVD within a year. Open to: Residents of the U.S. and Canada.

Search for Sex Books: Browse the list of sex book bestsellers at Amazon.com, including The Adult Video News Guide to the 500 Greatest Adult Videos of All Time.