What PageRank may I expect to receive in next PR update?

This may seem to be a pointless question, but I am not entirely sure how sites are assigned a PageRank and the Wikipedia article is a bit confusing.

My site's current PageRank is zero. Since last PageRank update I have exchanged links with many sites ( the link to my site usually being in a specific link page ):

Bach Cantatas Website - Home Page PR 6
Welcome to Classical.com PR 6
Classical Music CD and Concert Reviews - MusicWeb International PR 6
Andreas Scholl PR 5
Impulse Classical Music Website PR 5
Classic Cat - the free classical music directory PR 5
The Male Soprano Page PR 4
Hier sind: PR 3 ( I'm not exchanging links with them but they seem to be linking to me permanently. PR3 is the PR of their links page which is higher than the front page's PR )
Male soprano & countertenor, Aris Christofellis. Entry page. PR 2

( The PageRank values are the PR of the sites' front page but not of their link pages where my link is ( if that matters ) ).

Is it possible to calculate what PR I will receive in the in the next PR update ( this month? ) ?

not really.

i bet you will be between 0 and 9 (come on, no one is a 10 but google them selves )

either way, it's pretty much a pointless figure that has 0 bearing on anything search engine related.

I'll just keep exchanging links then. Am I right that the next update is in December,?