I think there is a PR update going on. My forum went from unranked on http://www.gaspumpstop.com/forum/ is suddenly a Pr 4 on Firefox toolbar even though the site is only 2 weeks old. Usually when I see a PR come out of nowhere like that it means a update is going on.
its not showing any PR here, may be the site you visited before you visited your site has PR4, it happens some times in FF
No it was definitely showing pr4 for a few hours. I would leave and come back and still PR 4 on the forum page only. It is now gone though. I have had the same thing happen in the past and what happened was google went through an update within the following days after that happened. So I think an update should be happening any minute.
schuks! One of my sites just went up last July or Aug? from pr 0 to 4. Just check a minute ago, and I am down to PR0!!