Law & Order has gotten an order for four additional episode bringing this season's episode count to 20. While there has been talk of a 21st season, technically the show has not been renewed and Angela Bromstad confirmed that at today's TCA session. But they are also looking at another Law & Order spinoff originally born from the possibility that this would be Law & Order's final season.
Perhaps also spurred by CBS' success with NCIS: LA, Law & Order: LA is being considered. Bromstad said that it was not an either/or situation between the original Law & Order and Law & Order: LA and that each will be considered separately.
The Futon Critic has a good summary of the other scheduling and development news from NBC today.