We currently only support countries that are supported by the major payment processors we integrate with. E.g., PayPal will not process any checkouts for buyers located in Egypt:
...and Google Checkout does not offer new buyer-account registrations in Egypt:
However, Authorize.Net should allow any buyer anywhere to pay with a credit card, so we will add Egypt to our country list for those cases. Just bear in mind that, if you are accepting PayPal or Google Checkout payments, buyers who select their country as Egypt in the cart and then proceed to checkout with PayPal or Google would then find themselves unable to proceed with checkout. To prevent this confusion if a significant number of your buyers will be located in Egypt, then you may want to consider using only Authorize.Net alone as your sole checkout option.