2013: This website no longer exists. I’ve updated links to the latest version stored in the Internet Archives.
There’s a new website on Adventism and apologetics – it looks really good. Excellent design … sites like this usually make me want to redesign mine, but I don’t have the time or the talent for that.
Dies Domini “is a internet research center, dedicated to promoting an ecumenical dialogue between Catholics and Seventh-day Adventists. Founded by former Adventists who embraced the Catholic faith, this ministry exists to glorify Christ in faithful service of His Church.” 
Most of the articles are in PDF format, but they are small, and download fast (I’m using a 56K modem.)
Journeys home from Adventism to Catholicism – there are 4 linked.
I recommend the essays one, as it’s the fullest, with the most interesting topics (for me.)