it will pass by about 6%, 53% to 47%.
all polls except a few outliers reflect this.
http://en.wikipedia.org/wiki/California_Proposition_19_(2010)#Polls
the poll you cite that has it trailing used a sample size of 448 likely voters. the best poll by PPP with 2,004 likely voters has it ahead by far. they also did cross sections that allow you to see how californians feel about 19 by age, gender, political affiliation, etc.
i did a simple breakdown and factored in a higher turnout of conservative voters based on predictable midterm election politics. i also estimated the undecideds to break decidedly for "no". with all these factors AGAINST prop 19, it still passes comfortably.
i encourage you to tell me how i went wrong in my calculations and why you feel prop 19 will not pass, despite a litany of evidence to the contrary.
the link to the PPP poll is within the quote, and ocntains all the info you need to dispute me if you wish.