You can contact the US Embassy for all passport related matters by visiting: US Embassy or you can reach them by phone at 1-877-487-2778.
It is best to contact them before you book your travel. You may find that in addition to a valid passport, a travel or transit visa may be required by the country you are visiting or connecting through.
The need for visa and other related entry requirements vary greatly based on your nationality and country of destination. You will need to contact the US embassy for the specific country to obtain more thorough information.
To order passports online visit: VISA Info which provides an affordable and convenient ordering process and they may be able to answer some of your questions as well.
Another great site for helpful information is: TSA Passport Info.