All signs point to August 19
According to a Danish site, Canon will be making their next round of PowerShot & EOS announcements August 19, 2009.
The PowerShot lineup will receive its updates. There will also be 2 SLR's according to multiple sources. The obvious 60D/7D camera and a 2000D/T1.
Another email stated August 25, 2009 would be the day for announcements, but my money is on the 19th.