I live in Bergen, so if you got any questions, please ask!
As the cruise terminal is located almost "in the city", you will probably get time to walk a bit around, and see the city for yourself. You can take a look at Bryggen/the old port, where you also will find a lot of museums, like the hanseatic museum, the Rosenkranz tower, and Haakonshallen.
You probably also want to go to an excursion to the home of "Edvard Grieg" at Trollhaugen, see the Aquarium of Bergen or visit Fl°yen.
I think this will be a great guide: www.bergen-travel.com
Ask if you got any questions!
If you want to look up excursions and adventures at the other ports of your cruise, I guess Hurtigruten will have some information about what to do, and propably some brochures.
Good luck with everything!
Have a nice trip!