SAN DIEGO - The likenesses of Spider-Man, The Incredible Hulk and other Marvel Comics icons will be emblazoned on stamps the Postal Service will unveil Thursday to coincide with the Comic-Con International Convention in San Diego.

According to the USPS, the 41-cent stamps will be sold in sheets of 20, half featuring portraits of Marvel Comics Super Heroes and the other half depicting covers of individual comic book covers.

Also featured are the images of Captain America, Elektra, Iron Man, Spider-Woman, Sub-Mariner, The Thing and Wolverine.

The stamps go on sale nationwide Thursday after a dedication ceremony at Comic-Con by USPS and Marvel representatives.

Ten characters from DC Comics were immortalized on USPS stamps that were released at the Comic-Con convention last year.

The annual four-day convention, touted as the largest gathering of its kind, draws thousands of animation, science fiction and pop culture enthusiasts to the San Diego Convention Center.

In recent years, it has also attracted Hollywood actors and studio heads, who use the event to release or promote films and television shows.

Celebrities slated to appear at this year's convention include actors Jessica Alba, Nicolas Cage, Edward Norton, Josh Hartnett and Robert Downey Jr., comedian Dane Cook, author Neil Gaiman, cast members from television's "Lost" and "Heroes," Matt Groening, creator of "The Simpsons," and artist Paul Pope, according to organizers.

The convention features hundreds of exhibits, seminars, art shows, gaming, autograph-signing sessions, film screenings and a masquerade party.

According to organizers, Comic-Con, now in its 38th year, drew about 123,000 people over its four-day run last year.

Doors to the convention open at 10 a.m. Thursday.

Single-day tickets are $25 for adults and $12 for juniors 12-16 and senior citizens. Children under 12 get in free with a paying adult. Tickets for Saturday, however, are already sold out.