Radio coverage will be provided by Radio Le Mans, who do a great job and will provide a reliable feed throughout the event, including some practice/qualifying sessions as well. Check out their website for coverage times.
Television coverage of N24 proved to be a little sketchy last year. In 2008 the official race website offered free streaming video, although it was problematic at times. But in the absence of anything else it did the job okay. Other options for possible TV coverage include German TV channel DSF and MotorsTV. If you find a link or have a tip for good TV coverage of the race please leave a comment below.
UPDATE 23 May: Also try this link from sport auto for a live video feed during the race.
[Thanks to Chris for the tip]