Need to have a professional painter look at it. You'll need to decide if you are going to try and fill in the grooves before painting or leave them. That will make a difference in price and the process the painter uses.

There are also some plain, paintable wallpapers that can be applied over the pine.

Shellac primer and paint.

http://houzz.com/photos/1929757

When I painted our wood panels, we used TSP to wash down and a Zinsser 1 2 3 primer, then paint. That prep work made the paint adhere well and we had no problems. First,
I would look at Judy M's first pic with the white trim...really looks great.

I really like the idea of 1st painting the trim before painting the whole thing for 2 reasons. One it's always a good idea to try out ideas in steps before any permanent changes that would be hard to undo. Secondly, and even more importantly in my mind, I loathe the idea of painting over wood particularly if it is in a craftsmen or victorian house! I cringed while watching Sarah 101 today when she painted over all the old oak walls & trim in a dining room update!

Another option would be to cut the paneling off at wainscoting height, paint the bottom and put sheetrock on the top.