Usually google do its PR update after 3 months but last PR update was after 5 or 6 months, it depends on google, It would be in March or April now.
I think that there is no fix time about Google Page Rank update, but many users predict times such as 3 months and 6 months.
Wasn't there a thread with the VERY SAME TITLE posted a few hours ago? I mean yeah, it's natural that some guys don't use search and don't go through threads but comeon, it would be reasonable to expect that you at least glance at the first page of the section that you're about to start a thread in.
The only way to find out is when Google tells you there is an updated PR coming out. But *for the most part* I've noticed over the years that they update it only 1 or 2 times max a year.
Just worry about seo of your site and backlinks. You never know when google will update could be a few months or late next year. Just make sure to keep working on your site and you will improve in search results.
i think google will update on January if they update every three months like their usual thing but if they decided to use their previous algo i think it will update on march.
I'm also waiting for the next PR update. Both my blogs manage to get PR2 even though I dont know anything about backlinks. Now that I'm actively getting backlinks through commenting on blog as high as PR8, I guess my blog can get higher PR.