This might be a good book if you're completely new to SSAS:

I don't know what other people around here think but I thought that it was a pretty easy read for those that are sticking their toes in.

Microsoft® SQL Server™ 2005 Analysis Services Step by Step

http://www.microsoft.com/MSPress/books/8592.aspx

And get yourself a Kimball book if you don't already have one.

🙂