Page Rank is a very important factor for any blog or website. For example, this blog (South Asia Blog) has a PR 6 in a scale of 10 according to Google. Six is considered to be a good one but 7 is obviously much better. I wish that someday, I can have a blog with PR 7 or 8. Anyway, there is perhaps a lot of expectations among the bloggers that there will be an update in PR in the first few days of October 2009. The problem is that only Google officials know when will be the next update and if you ask my opinion then I would say that there should PR update at the beginning of each month.
After all, Google is now the giant in search engine market and no one is near it. Good thing is that Google Caffeine is coming any day and then we should expect much faster indexing and updating. I have noticed that some of my entries of this blog and another blog get indexed within even 1 minute after uploading. It shows that things will be faster when Google Caffeine comes out in full force.
So, to answer the original question, most likely there will be a Page Rank Update at the first week of October 2009 but if it does not happen then do not blame me because I am no way related to the mighty search engine.