+1(514) 937-9445 or Toll-free (Canada & US) +1 (888) 947-9445
Check my post here:
http://www.canadavisa.com/canada-immigration-discussion-board/celpip-my-experience-t155078.0.html

You'll need little to no prep if you're already living in Canada for some time.
I'm here since April 2012 and had NO problems scoring high in the CELPIP test.
 
I gave my test 2 weeks ago and scored high in all categories. Go to CELPIP website where they have few sample questions to give you an idea about the test. It is a simple test. General English.
 
go to a public library you will find lots of books with cd to practice, I took the IELTS looks like CELPIP is a little less complicated