Apply Transactions .DAL &BLL

Question

I hav to do project work in which adding a new user means inserting that details into 3 tables ; also insert data into 3 more tables.
For that i am using DAL and LINQ for each insertion,ie  in DAL I ahv different methods to insert data into tables.
I would like to know that how to apply transaction in presentation layer so that failure in any of the table should causes the rollback of ever insertion.
I am setting the dbconnection in config file.
use linq to insert and upadte tables
Could you please help me.

Thanks in advance