how to replace wheel bearings?

Does anyone know how hard it would be to replace the right rear wheel bearings on my 96 glx? I found a kit with all the parts http://www2.autopartsauthority.com/parts/autopartsauthority/quote.jsp?year=1996&product=K8020-37953&application=000388257&part=Wheel%20Bearing%20Kit&category=K WHat tools would I need and how long would it take? Also how much would it cost if i took it in to a mechanic?

Rear disc or drum brakes?

if it is drum real easy, if disk a little harder
17 mm to take off tire
drum, pliers to remove dust cap, and cotter pin, adjustable to take of nut on spindle after removing lock cap on nut, brass or steel punch and hammer to knock out graese seal and races for bearings, bearing race installer or punch and hammer to install races, bearing grease to pack new bearings.

disk, allen head bit, not sure of size, to remove caliper and bracket asembly then same as drum.

plobably 1-2 hrs at garage times local rate $80 in ct.
80-160

all GLX models came w/ disks in the rear, VR6 motor.
i'll reiterate what mjgjr72 posted, but go into more detail.
after you remove the caliper and carrier,and spindle nut, the rotor should slide right off the spindle. to remove the bearings, i've found it easiest to use a flathead screwdriver and a hammer. if you wipe the grease out you can see notches cut on the inside of the rotor. you can put the plathead on through the notch so that it sits on the bearing/race. hammer the end of the screwdriver a few times. then switch to another notch so that the bearing comes out straight, kind of wiggling it out side to side. it takes a lot of force so dont be shy.
after you get the old races out, hold on to em. pack the new bearings with grease. i usually just grab a glob of it in my palm and try to squeeze it through the bearing. if you dont have a press to press in the new races, you can hammer them in. place the race inside the rotor. then place the old race on top. you can either use a large socket or block of wood, and hammer down the whole thing. the purpose of using the old race is that a) you dont damage the new one and b) the new one will sit all the way down.
after the race is installed, throw some more grease in there for good luck, then put it all back together. hope that helps.