SPOILER: There is a scene after the credits: Dr. Selvig meets with Nick Fury, who asks him to examine the Tesseract from Captain America: The First Avenger (2011). Loki appears in a reflection on the wall influencing Selvig to agree.
Part of the closing credits is shot through the Bifrost, with the camera flying through the celestial realm of Yggdrasil, finally ending at Asgard. At the end, the film title appears with a small lightning strike within it.