Want to process credit card transactions for free? It's possible with Google Checkout (as a promotion through the end of 2007). Want to do it on a free production-quality application server? Then you want GlassFish. Inderjeet has put together instructions for doing just that by integrating with Google Checkout's REST-based XML API.

Wotif.com provides cheap last-minute hotel reservations in over 35 countries and it is specially popular in Australia, New Zeland and nearby locales (see this article). The site has been using OpenSource products for a while but they just switched to GlassFish - see Jamey's Adoption Story.

Wotif is a particularly interesting site: their production servers support around 10,000 concurrent sessions and the site averages almost one million users, who make over 110,000 bookings each month; I'd say that means GlassFish is ready for production! Wotif uses ehCache for caching over horizontally scaled hardware, is using Sun's v40z boxes and complements the community support for GlassFish with Sun's commercial support offering.

More details are available at Jamey's Story and at the detailed Adoption Questionnaire. And, if you are interested in the past history of the site, check the Netcraft Report.