Besides the Scopolamine Patch -- which requires a doctor's prescription -- here are a few of the things that we've tried:
Chewable Bonine tablets (generic: meclizine), or Chewable Dramamine (generic: Dimenhydrinate), both available over the counter at your local pharmacy. Don't swallow them, but let them dissolve in the mouth or under the tongue, as they get absorbed into your system much more quickly that way (see http://www. yachtsdelivered.com/seasick/). This seems to be as effective as anything.
We've also used various ginger products as well, including candied ginger root, and drinking lots of ginger ale (Canada Dry). Sea-Band ginger chewing gum (http://www.sea-band.com/gingergum), is now being offered by Landfall Navigation.
Motion Eaze oil (http://www.motioneaze. com/motioneaze.html) placed on the skin behind your ears; available from Landfall Navigation.
Davis Queaze-Away Wristbands (http://www.davisnet.com/marine/products/marine_product.asp?pnum=00400); again, also available from Landfall Navigation.
Some of these can be found at the local pharmacy, Walgreens, Walmart, or CVS.
Some other references: