From WineLog.net and Stranger Studios:
WineLog keeps a record of wines that you have tried when you venture to try a new type or variety of wine, you are taking the risk that you will either love it or hate it. WineLog provides you with a free way to track your preferences on new wines, including the specific information about the wine, as well as personal and public comments and one to five-star rating.
After trying a new wine, simply login and select add wine to log. You will fill out a simple form about the wine and then WineLog will be added to your log. With this feature, you can remember which wines you enjoyed and purchase them again, and you can also remember which wines to avoid in the future.