When I plug my ipad into my PC, nothing happens and it says "not charging" on my ipad screen

You must have an older PC (windows). The USB ports cannot handle or charge the iPad. Make sure you have the latest version of iTunes. Older versions will not recognize the iPad. Do this and you should be fine.

The 'not charging' message is to be expected, a lot of computers don't provide enough power to their USB ports to charge iPads at a sufficient rate (the iPad might still be charging slowly even though it says 'not charging'). From http://support.apple.com/kb/HT4060 :

The fastest way to charge your iPad is with the included 10W USB Power Adapter. iPad will also charge, although more slowly, when attached to a computer with a high-power USB port (many recent Mac computers) or with an iPhone Power Adapter. When attached to a computer via a standard USB port (most PCs or older Mac computers) iPad will charge, but only when it's in sleep mode.

A standard USB port can put out a max 500 mA on a port (which is the max that the USB standard calls for). On a lower-end PC, the USB ports often share a bus that further imposes a limit on the total amount sent to all the ports.

iPads require 1000 mA to charge (note the power output information on the iPad power brick). I don't know of any PC vendor, other than Apple, that equips their systems with USB ports that can put out that much power. I presume that there are probably vendors of high-end motherboards for do-it-yourself PCs that offer such a feature.

To charge your iPad, you will need to use the provided charging accessory, a certified iPad-compatible accessory, or connect the device to a Mac computer with a late-model Mac (well, at least since late 2009).

Saying 'not charging' is totally normal. And actually your iPad does charge...but it's a trickle charge. as in charging it will take hours and hours and you can't be using it at the time. The best way to charge it is as Penguin says, plugged into the wall.

Hey download this http://event.asus.com/mb/2010/ai_charger/ then use WIN RAR to extract it run the program then before you press finish unplug all disks for example, Ipad, USB thumb drives, i phone, ipod, etc. MAKE SURE YOU PICK RESTART NOW> after restarting you can plug your iPad in to charge. This gives your computer's USB ports more power.

Thanks a lot man this works for me.... now its so easy to handle ipad hats off man thank