Scoott Gu, in his endlessly useful series of articles on Linq to SQL, has an article on how to use Stored Procedures with Linq data model.
Apart from often quoted reasons like access speed and logic used in Stored Procedures, the positive side of using Linq with SPs is that the retrieved entities are strong typend and updatable through Linq. Having said that, it is also possible to use Stored Procedures on the insert/update/delete side.
Multiple results returned by SPs can be handled, as well. User Defined Functions are supported directly in Linq queries.