Eduard Blacquière in his excellent article SEO Question: does a non-indexed page pass on PageRank? said that we actually need to rephrase what the definition is of being in Google’s index, and that he would opt for the following guideline:
A page need to have an incoming link visible to Google to accumulate and pass on PageRank.
And he continued:
So, does a non-indexed page pass on PageRank? Yep, it does! (if the links to and/or from the page are visible to Google).
What do you think?