Why is the PSVita not charging through the USB port on the PC

I can confirm the US and EU stores are not live. Attempting to access the PSN store with a US profile on a Vita as of 12/31/2010 will encounter a cannot connect error until they are launched along side the Vita rollouts in those markets.

The Vita displays a charging animation on the top right battery icon; green bolts of electricity pulse over the icon when it's charging. It only does this when using the wall charger that came with the Vita as it draws a larger amount of power than it can from a standard USB port. The PS Button will light up orange while charging as well, so you can see that it's charging when the power is off.

The Vita will also passively and very slowly charge when it is plugged into your PC. There is no visible indicator of charging when not plugged in via the wall socket. This is because the Vita draws about as much power from the PC as it takes to operate. It will charge if you plug it into your PC and leave it in a low power state (screen off) but there will be no indication of charging except that the battery meter will eventually fill. No animation will play.

If you turn the Vita off while plugged into your PC the PS button lights up orange, so if you're unsure if a socket is charging the Vita, turn the Vita off and plug it in.

If you're using the Vita while charging from USB your Vita's battery may be discharging faster than the USB port can charge it. Also make sure the plug is plugged in the right way; the Vita will only charge if the PS logo on the cord is facing up, up being the direction of the screen of the Vita. It turns out the cord fits in backwards, it just doesn't charge.