Hi!
There is only one ski resort near Granada: Sierra Nevada.
It is at half an hour from Granada itself, located in the side of one of the highests mountains of the Iberian Peninsula (Veleta).
It has 67 skiable kilometers, 20 ski-carriers (don't know the technical name) and 53 ski ways.
I have enjoyed various times this ski resort. Almost always I have had sun (and as warm weather as to be just skiing with a t-shirt). From the highest places of the resort you may even see Africa! (wonderful sights).
Also, its nights are crowded, lots of discos (believe if I tell you that it is tiring to dance till the morning and then practice ski).
Finally, this is their website:
http://www.sierranevadaski.com/ Enjoy!
Fernando