Bethesda and Interplay have settled a long-running dispute over the Fallout IP. Bethesda bought the Fallout franchise from Interplay in 2007, but licensed back to Interplay certain rights to sell pre-existing Fallout games and to develop and operate a Fallout-based MMO. The MMO portion of the licence contained various conditions, including that Interplay secure funding and start full-scale development of the MMO within 2 years, and launch the MMO within 4 years.
In 2009, Bethesda launched a lawsuit against Interplay for trade-mark infringement (on the basis that Interplay was not complying with the trade-mark provisions of the 2007 licence in its activities relating to the pre-exising Fallout games) and breach of contract (on the basis that Interplay had not begun developing the MMO).
Reports are that the settlement includes the cancellation of the MMO licence and the reversion of all MMO-related rights to Bethesda, the cancellation of any other Fallout-related IP rights granted to Interplay, and a $2 million payment by Bethesda to Interplay.
Coverage of the historical dispute here (Gamasutra); coverage of the settlement here (JoyStiq).