Can you recommend a site or a book where I can learn BI for sql server 2008. I know there are tons of books out there by searching google. But I want your recommendations which could save me lots of learning time.
That area is fairly vast and as such you are unlikely to find one source that covers it all.
You would need to take a look at:
Sql Server Analysis Services
The recently added Tabular Model
and Reporting Services
to name a few of it's moving parts.
If you are relationally minded, then you may find you have to "unlearn" a few ingrained ways of thinking to get your head around the data structures that underpin multi-dimensional databases.
The kimball methodology is common place in that arena so may be you can start by taking a look at his books on datawarehousing and work your up?
* The Data Warehouse Lifecycle Tookit
* The Data Warehouse Toolkit
* The Data Warehouse ETL Toolkit