hey guys im just changing my front brake rotors and i thought i might as well change the wheel bearings. i have noticed the wheel bearings that are on the car atm have no cases and the new ones i have broght have a casing which i can take on and off
my question is am i meant to use the casing?

The inner part of the bearing is a "Cone", the outer part is a "Cup".
The cups and cones are matched, so yes, use the cups.
Remove the cups from the new disc rotors, and fit the new cups, grease the cones, put some grease inside the hub, fit new hub seals ( must be seated all the way to the bottom), clean the stub axle, polish ( fine wet & dry sand paper), the seal surface on the stub axle.
If these instructions are not clear, get yourself a workshop manual, read it, understand it, then do it.

hey mate cheers heaps i ended up using the cups that are all ready in the rotors the bearings fitted perfect into them
with the seals i lightly taped them in untill they wouldnt move no more
the only problem i think i have now is that the rotor is on to tight ill jack it up and see is there a certian amount of times a wheel should spin freely?

I noticed you didn't comprehend what I said......

Thats one of my pet hates.
Using another brand cup.

as CJH said, its best to tap OUT the cups in the rotor, and install the cups that come with the rest of the bearings.

Sure, most brake places, mechanics will just slap in new bearing races in the cups that are provided in the new rotors, but its not really professional. I think there's a show on SBS that shows this practice perfectly - bush mechanics.

There's no half job on the motion of a car, ie: brakes, wheels, tyres, steering and suspension. the rest that gets it going, cut corners there.