This blog talks about different procedures of moving SSAS 2005 Databases to SQL 2008 Databases

Question: How to Migrate Database from SQL 2005 to SQL 2008

Scenario 1 - Moving SSAS Databases from SQL 2005 SSAS to another Server where we have SSAS 2008 Services

Procedure:

Backup SQL 2005 DB and restore it on SQL 2008 -

http://blogs.msdn.com/b/karang/archive/2010/08/10/migrating-olap-ssas-2005-database-to-sql-2008.aspx