According to a post on VG247.com, the latest installment of the epic Call of Duty series will be called “Call of Duty: Black Ops”.
The post also sugests that the game will differ in it's setting(s) too...as in, more than one era. What there (possibly) will be are missions in Vietnam, Cuba, South America and even the infamous SAS mission during the Iranian embassy siege in London in April 1980. The blog post states that the game, which is currently being developed by Treyarch, will take place in various battle arenas in history such as, during the Cold War, to good old World War II and up-to present day.
Also, (allegedly) Zombie Mode will be back in some form or another! w00t!, as well as dedicated servers. Two major bugbears everyone had with Modern Warfare 2 PC.