I've not found much detail but apparently the BBC's Luther will return in 2011 for "two hour-long specials". One would hope that Ruth Wilson will be returning as Alice Morgan. Note the use of the word "specials" as they can't very well call it a series with just two episodes.
Still, it's welcome news even if it's only two episodes.
Sherlock will also be returning for three more episodes.
Sherlock is also out on DVD. I'm tempted to buy it as it includes an un-broadcast pilot episode that according to the IMDb Zoe telford is in, whereas in the broadcast series she was introduced in the second episode and only makes a fleeting appearance in the third.