I think the Toshiba because of its USB host is very picky about the charger it uses.
I have tried 3 now!
No name brand - 5v 500ma. Charges the phone just fine....but doesn't charge it quick enough, when navigating etc, it uses more power than it can charge
Blackberry 5v 500ma - lovely long cable length, better than the one above but same problem.....just drains a bit slower!
Samsung 5v 700ma - cable a bit short but charges the phone fantastically and works just fine!
Edit - Most phones from most of the major phone companies will support charging through micro USB. I wish they kept with mini usb.....micro is too flimsy!!