I just discovered that GiftCardRescue buys open-loop gift cards.  They have been doing so since 2008, but I just noticed recently.

As far as I know (and they agree) they are the only secondary gift card marketplace to offer to buy any open-loop cards.  Discover cards are not included, but those are rare.  They will buy any non-reload-able card from any issuer, that has not yet been registered to a person.    They resell the cards on their site for a 4-7% discount.  Because you are not paying the additional up-front fee, this amounts to more like a 10+% discount, a real bargain if you are looking to buy one of these cards.  This is a much better option than buying them new from a store.

This is a big deal, as those cards in particular have been a big part of the problem when it comes to high fees and short expiration dates.  Now consumers have at least one option to get rid of those cards before they self-destruct.  It remains to be seen whether the federal gift card legislation as part of the Credit Card Reform Act of 2009 will truly squash these fees and expiration dates, or whether many loopholes will be exploited.

Another option to cash out of open-loop cards is to find a friend with a merchant account to run it through their physical or virtual card processor to extract the remaining value.  The merchant processing fee runs around 3% for most merchants.