I've just found an excellent document that has come out of the SSAS team. It details all properties of the Analysis Server (SSAS2005). There's a real multitude of them them so this is an invaluable document.
The paper is here: http://download.microsoft.com/download/4/f/8/4f8f2dc9-a9a7-4b68-98cb-163482c95e0b/SSASProperties.doc#_Toc136412586
What would be good now would be a whitepaper on performance tuning that explains how these properties should be configured. Here's hoping!