I've noticed that the front wheel on my Specalized rockhopper has got a pronounced "wobble". When it's attached to the fork, I can take the rim and move it about 5 degrees away from "normal" either side.

I'm guessing the bearings are starting to go? Is this something I can fix or do I need to get a new wheel/hub?

What hubs do you have?

sounds like you may need to adjust the cones (assuming cup and cone hubs). requires flat spanners of the correct size and some patience. Or ask your LBS to do it

maybe the cones just need adjusting if the bearings are the loose type (as opposed to cartridge)

I've no idea about the hubs. They're listed on the specialized website as being "Specialized Hi Lo, forged alloy, double sealed, ground race, 28h"