This is a list of kits, instructions, books and components for people who are interested in getting started with wearable electronics.
Kits and a basic instruction book:
https://www.etsy.com/shop/muppin (the kits come with the book)
Sew Electric by Leah Buechley.
Starting at the beginning, with patterns for interactive, light up and smart textiles, going up to programming a micro-controller. Leah Buechley is the original designer of the LilyPad.
Switch Craft, Alison Lewis with Fang-Yu Lin, book of battery-powered fashions to make.
http://www.amazon.com/Switch-Craft-Battery-Powered-Crafts-Make/dp/0307395448/
Adafruit Industries. Conductive thread, micro-controllers, sensors, video tutorials, Arduino (and lots of other geeky stuff).
It's also worth looking at their archives of Wearable Wednesdays, Show & Tell, and Ask an Engineer. As you try and learn more and more, the geek-talk makes more and more sense.
SparkFun. Components, micro-controllers (especially Lilypad ones), Arduino, conductive thread, kits, and multiple video tutorials for both e-textiles and other geekery.
Kokabant, also known as How To Get What You Want. A reference resource for online instructions, reviews of components, classes.
Fashion Geek: Clothes Accessories Tech by Diana Eng. This may be out of print, but s worth tracking down, and some of the projects are great fun, and not too hard. Heavily illustrated.
http://www.amazon.com/Fashion-Geek-Clothes-Accessories-Tech/dp/1600610838/
To Engineer Is Human by Henry Petroski. Not about wearables, or even electronics, but a fascinating discourse on designing, building and engineering.
http://www.amazon.com/Engineer-Human-Failure-Successful-Design/dp/0679734163/
Lynne Bruning, and her E-Textiles Lounge. http://www.lbruning.com/ has a link to http://etextilelounge.com/, which has plenty of tutorials and product reviews, and general good advice. The eTextile Lounge is also an active group on Facebook, and there are some wonderful things posted there of e-textiles, wearable computing events and conferences from around the world.
Aniomagic. http://www.aniomagic.com/store/ Kits with LED sequins, a tiny controller, all you need to light up a few tiny LEDs, and the means to program them on the go.
http://www.instructables.com/. If you want to know how to make just about anything, this is a place to at least start. There's no guarantee on the quality of the instruction, but some of the following terms are a start: lbruning, Arduino, LED sequins, e-textiles (with and without the dash and with and without the s), wearable computing, sewing LEDs, and many more. It's easy to end up pretty far afield from where you started, but it can be hugely useful.
Make: Wearable Electronics: Design, prototype, and wear your own interactive garments by Kate Hartman.