How do I find out what my phone's Firmware/Software version is on my Verizon phone?

Usually there are two ways to find this information:
One: Look under the battery. There should be a barcode with numbers above and below; listed in these should be S/W.
Two: In the phones menus you should find under "Tools and Settings", Phone Info.
 
For phones that have been flashed to a Moto UI, you should be able to find the S/W version under the icon for Phone Status in the Other Information menu.