Well, selling it with in the borders of Virginia, you're pretty much free to sell it without restrictions (you may want to make sure the buyer is a Virginia resident and over 18).
You may want to try and sell it in the EQUIPMENT EXCHANGE on AR15.COM or perhaps warrifles.com or the falfiles.com. If you sell to a buyer in another State, ensure it is legal for that person topurchase/own an assault rifle (I assume your FAL isclassified an "assault rifle")in thatState, i.e. there are no laws prohibiting assault rifle ownership in that State. Also,you'll have to send it to an FFL in the buyer's State for transfer. Many FFLs will not accept a shipment from a non-FFL, even though it is legal.Therefore, you may have to get an FFL in Virginia to actually ship it for you.
Secondly, I'll be happy to give you $400.00 for it.