A quick check of the NEC 2008 definition section, might yield an answer. GFCI protection is required in all wet, and damp locations. It is also required in some dry locations, where specified in the code.
Location, Damp. Locations protected from weather and not subject to saturation with water or other liquids but subject to moderate
degrees of moisture. Examples of such locations include partially
protected locations under canopies, marquees, roofed open porches, and
like locations, and interior locations subject to moderate degrees of
moisture, such as some basements, some barns, and some coldstorage
warehouses.
Location, Dry. A location not normally subject to dampness or wetness. A location classified as dry may be temporarily subject to
dampness or wetness, as in the case of a building under construction.
Location, Wet. Installations underground or in concrete slabs or masonry in direct contact with the earth; in locations subject to
saturation with water or other liquids, such as vehicle washing areas;
and in unprotected locations exposed to weather.
Let us also look at section 406.8 Receptacles in Damp or Wet Locations.
(A) Damp Locations. A receptacle shall be considered to be in a location protected from
the weather where located under roofed open porches, canopies,
marquees, and the like, and will not be subjected to a beating rain or
water runoff.
According to this section, you might also need a weatherproof cover for the receptacles.
A receptacle installed outdoors in a location protected from the
weather or in other damp locations shall have an enclosure for the
receptacle that is weatherproof when the receptacle is covered
(attachment plug cap not inserted and receptacle covers closed).
You might have a bit of wiggle room if the space is completely enclosed, but you still might consider GFCI protection just to be on the safe side.
Section 210.8 Ground-Fault Circuit-Interrupter Protection for
Personnel. specifies locations that require GFCI protection.
(A) Dwelling Units. All 125-volt, single-phase, 15- and 20-ampere receptacles installed in the locations specified in (1) through (8)
shall have ground-fault circuit-interrupter protection for personnel.
(1) Bathrooms
(2) Garages, and also accessory buildings that have a floor located at
or below grade level not intended as habitable rooms and limited to
storage areas, work areas, and areas of similar use
(3) Outdoors
Exception to (3): Receptacles that are not readily accessible and are supplied by a dedicated branch circuit for electric snow-melting or
deicing equipment shall be permitted to be installed in accordance
with 426.28.
(4) Crawl spaces — at or below grade level
(5) Unfinished basements — for purposes of this section, unfinished
basements are defined as portions or areas of the basement not
intended as habitable rooms and limited to storage areas, work areas,
and the like
Exception to (5): A receptacle supplying only a permanently installed fire alarm or burglar alarm system shall not be required to have
ground-fault circuit-interrupter protection.
FPN: See 760.41(B) and 760.121(B) for power supply requirements for fire alarm systems. Receptacles installed under the exception to
210.8(A)(5) shall not be considered as meeting the requirements of 210.52(G).
(6) Kitchens — where the receptacles are installed to serve the
countertop surfaces
(7) Laundry, utility, and wet bar sinks — where the receptacles are
installed within 1.8 m (6 ft) of the outside edge of the sink
(8) Boathouses
Depending on the porch construction, this space may or may not be considered "outdoors". Because "outdoors" is not specifically defined, I would air on the side of caution and install GFCI protection and weatherproof covers. Use your best judgment and the definitions of damp, dry and wet locations to make a decision. Keep in mind, however, the inspector will have the final say as to what is and is not required.
