Here are some good links to find R/C info, accessories, and tutorials.
Great source for everything Xmod & Mini-Z! They have the best selection of after market parts for your cars and trucks. They aren't the cheapest place to get everything, but have the highest quality in lithium, electronics, and motors. They also carry many discontinued Gen 1 parts and upgrades.
This is a link to the Xmod and ZipZap section on Radio Shack's website. Use this for reference only - we get great deals and service from our local Radio Shack in Lewisburg. Tell them you are with Innerstate 180 and they can even check other stores for discontinued 1st Gen parts and cars.
This is the Xmod official website. You can check out detailed info and pictures on all of the official Xmod products and accessories.
This site has some good reviews on after-market Xmod upgrades, like motors, electronics, nitro kits, etc. It also has some good tutorial resources for modding your cars.