Hi Karthik,
Links to tutorials on BRF+ can be found in the space home page for Business Rules Management here: http://scn.sap.com/community/brm
Check the Overview links and the featured content list. I recommend looking at the DSM videos listed here http://scn.sap.com/docs/DOC-29158 as this will give you both an understanding of the Decision Service Management governance tool for BRF+ (through which all new functionality for BRF+will now be delivered) and also gives some simple tutorials of authoring BRF+ rules.
Rgds,
Jocelyn