How do I properly feed coax through an outside wall?
After following Tester101's answer, here is a detailed step-by-step with pictures of how I fed the cable.

Shopping list


 Low voltage bracket $1.30
 Premium Waterproof Silicone 2.8 oz $3.98
 Leviton 1-Gang Midway CATV Wall Plate - White $2.79
 Milwaukee 3/8 in. x 18 in. Bellhanger Bit $12.47
 Coaxial Cable Feed-Through Bushing - White $1.97 (comes in 2 pack)
 RG-6 Twist-On F-Connectors $5.48


Sub-total $27.99

You may also need:


RG6 cable (if you don't have any lying around it's $0.29/foot at Home Depot)
3-way cable splitter $6.97


Tools required


Drill
Universal Cable Jacket Stripper $4.88
Dry-wall saw (or something for cutting a hole into the drywall)


Prep work



I used some brown packaging paper, cut a piece out for the corner and taped it using painter's tape in the area that will be worked on



On the outside, the cable will go into the cable box which is conveniently located about 2 feet away.

Step 1



I picked a spot that was in between the door frame and opposite wall to start drilling, about a foot above the ground.



Comes out clean on the outside. You'll want to leave the bit sticking out so you can feed the coax back inside.

Step 2





I took some existing cable and cut one of the ends, exposing the inside wire for better handling when feeding it back through the wall.

Step 3



I fed through the exposed end of the coax from the inside of the cable box so that the end with a connector can be added to the splitter.



At this point, you may need to add the 3-way splitter if you don't want to replace an existing connection.



Step 4



Before we feed the coax cable back inside, slide the plastic bushing onto the coax cable.



It's time to tape the cable to the bit to feed back inside.

Step 5



Using electrical tape, tape the coax cable to the bit.



Pull the drill bit back thus pulling the cable through the wall.

Step 6 



Press the plastic bushing into the outside wall. You may need to enlarge the hole slightly to push through the bushing.

Step 7



Cut the drywall and fasten the low voltage bracket.

Step 8





Strip the coax cable and fold the wire shielding against the outer insulation.



Push the connector onto the coax cable and twist the connector until the connector is firmly sealed with approximately 1/8" of center conductor protruding from the connector.

Step 9



Connect the coax to the back of the wall plate.

Step 10



Secure the wall plate to the bracket.

Step 11



Using a screw driver, I bent the coax to ensure it bends down as it enters the plastic bushing. Use the cable manufacturer's minimum bend radius to bend the cable to insure you don't damage it. I then used the silicone around the bushing as well as around the coax.