"Frank Castle is under the roof of Marvel Studios now and we hope to bring him into the fray shortly." As our sister site Spinoff is reporting, that's what Marvel Studios President Kevin Feige announced to the crowd during the Marvel movie panel at the San Diego Comic-Con last night. This appears to mean the Punisher is now as much a potential part of the Marvel "Cinematic Universe" as Iron Man, Captain America, the Hulk, Thor, and the rest of the Avengers gang.
Previously, film rights to the Punisher had belonged to Lionsgate, which made two Punisher movies -- 2004's The Punisher, starring Thomas Jane, and 2008's Punisher: War Zone, starring Ray Stevenson. The latter film was the source of much behind-the-scenes controversy, with Jane departing the franchise and rumors of strife with director Lexi Alexander. Like the Spider-Man, X-Men, Fantastic Four, Ghost Rider, Blade, and Daredevil films, Lionsgates' Punisher movies were made outside of the control of Marvel proper. (As was, of course, the infamous Roger Corman-produced, Dolph Lundgren-starring version from 1989.)
Feige's brief statement appears to be the only info about the Punisher making his Marvel that's out there, so it remains to be seen exactly how and when he'll join the fray.