This has actually been updated to reflect a lot of Server 2008 / SQL 2008 issues.  One thing I learned that has not yet been resolved:  Install Enterprise Portal, SSRS and SSAS all on the same machine.  Otherwise you will have great big problems!  As of this writing it is still an issue, mainly an OLAP problem / Kerberos issues.  So take my advice and install all 3 on the same machine!

http://technet.microsoft.com/en-us/library/aa497072.aspx