Can I charge USB devices from a powered hub that isn't connected to a PC?

Check: Transform a USB hub into the ultimate DIY gadget charger

I'm talking about a standard USB hub--those little accessories that multiply one of your PC's USB ports by a factor of four, five, six, or even seven. I took a spare seven-porter--the Belkin F5U701 ($20)--plugged its included AC adapter into a nearby wall outlet, and started loading it up with devices. A few minutes later, I was charging six devices via USB with no apparent problems--and I still had a free port available for yet another device.

Although the voltage is consistent across all USB chargers (5V), I believe the ampage does vary. I have heard reports that iPhones charge really slowly or not at all using a Blackberry charger. Same with Blackberry chargers, they are not all the same ampage for each model.

I would just buy a 4/6-way power surge-protected strip or something and plug all of your existing chargers into that.