Pull the bowl and impeller, then pull the 4 bolt bearing retainer at the front of the pump.  Sometimes you can reuse the packing seal, but best to replace that while your in there...so remove that too.  The whole
Shaft assembly will slide out the front of the pump.  Pop the snap ring off, press off the bearing and slinger bushing, press new bearing and slinger on, replace snap ring, reassemble.  The bearing/kit is available through any number of vendors.  I would recommend getting a whole rebuild kit and replacing all the seals/bowl bushings while you're in there....

Edit:  the bearing has be installed in the correct direction....take not of where the cutout is in the race before removing the old bearing, or ask the vendor for clarification as I imagine different bearing manufacturers construct the bearings slightly differently.