Hey Kip,
I thought I'd jump in on this. I've been pouring/painting/tying my own jigs for a long time and I'd like to share some of the things I've learned ...all too often the hard way. (Lest I forget, Jason's story of the bare hooks cracked me up.)
MOLDS: Do-It Molds is pretty much the main maker of molds and they have a good website. You can buy directly from them, but you'll probably get better prices at Barlow's, etc. They make a little over a million different molds so make sure you get the right sizes, and the right jig head...football, arkie, shakey head, Erie, etc. Each mold is going to cost $30 - $50.
LEAD: Forget the tire weights and only use soft lead. You can tell if it's soft lead by running your thumbnail across the lead. If you leave a trail...lt's soft.
HOOKS: There are many good hooks on the market. Personally, I use the black Mustad Ultra Point hook for most of my jigs. It's a good hook, it's sharp, it's strong and it's affordable. Owner also makes a good hook.
PAINT: You've got to paint your jig head and, to me, that means powder coat. Powder paint comes in many different colors. I use a paint stripping gun to heat the jig head, a pair of hemostats to hold the hook, a fluid bed to hold the paint (it suspends the powder and avoids clumping) and a cup of water to dip the hot jig head into. WAIT... THERE'S MORE. At this point the paint is very soft and must be hardened by baking it in a small tabletop oven. Hang the hooks on the grill or use a nifty holder sold by TJ'S Tackle...350 degrees for about 20 minutes and walaa. Make sure the eyes are open before you bake them.
SKIRTS: The easiest material to use is silicone strands which come in a myriad of different colors and patterns. They are attached to the hook using a rubber collar. (Many complain that over time the collar is going to rot which will ruin the skirt.)
Personally, I prefer to use round rubber for my skirts. To me, the rubber skirt pulsates more than the silicone and gives your jig a more lifelike appearance. The rubber comes in different diameters and different colors and you can do some cool things with it. One of my favourite colors is a black/brown skirt on a weedless 3/8 oz. brown w/ black sprinkles football head with a few strands of purple silicone and a couple thin strands of ultraviolet angel hair extending a couple inches beyond the skirt. Follow that up with your craw trailer of choice and you're good to go. You're not going to find that on a shelf unless you make it yourself.
RUBBER COLLAR, WIRE, OR THREAD: As stated, you run a substantial risk of the rubber collar braking over time. I use wire. Put the hook in the fly tying vise and place the rubber over the hook shank. Use about 4" of 26 or 28 guage wire under the hook shank. Hold one end of the wire with your left hand and with your right hand take two wraps around the rubber and the hook shank. Twist the wire together and use a needlenose pliers to twist tight.
I will also use Flymaster Plus fly tying thread whenever I'm making a hair jig (great for smallmouth). The thread will "dig in" to the hair when wire won't.
VISE: Try to use a good fly tying vise when tying your jigs. I use a Dyna King Baracuda.
As always, sorry about being longwinded.