I used this http://underthefold.org/2011/06/13/exam-70-448-study-guide-part-1/ (along with parts 2, 3, 4, 5 and 6) to prepare for this exam. These web pages have a list of relevant references that cover all of the topics that are examined. If you read through all of the info in these links (and, for me, some of the links and references on those pages) you should be good to go.
I passed this exam using this, so for me it worked.
And as a result of this exam preparation I was also able to sort out some security problems I was having with SSRS - for me, another nice win