Not sure if anyone has tried this, but for a recent school project I experimented with using wire wrap wires (or any 30AWG or thinner wires) for 'sewing' electronic components to fabric or clothes. Well, it's not exactly sewing, because it's more like weaving wires through the fabric, and soldering components onto the wires. Also, it doesn't really involve a sewing needle because the wire itself is good enough to penetrate through fabric. I like the solderability, because I am really not good at sewing. Also, these wires are available in many stores and are cheap. I've documented the process (with pictures) in this blog article: http://rayshobby.net/blog/?p=1128. If anyone has tried this, please feel free to share your experience.
You want me to wash my wire?
washingYour creation is washable. Remove the battery and wash the garment by hand with a gentle detergent.Note: silver coated threads will corrode over time and their resistance will gradually increase with washing and wear. To limit the effects of corrosion, insulate and protect your traces with puffy fabric paint. See my make your own electronic sewing kit page for more information. You can also revive exposed corroded traces with silver polish. Try this on a non-visible area first to see what it does to your fabric!
Washing: Once you have sewn your conductive thread into clothing to create your circuit, do not worry, because Yes the thread can be washed. You may use hand or machine washing (hand washing and hang dry is best). You can wash on a warm setting, and try to use a liquid detergent to avoid any surface deposition from soaps. And NEVER use bleach. Do not get carried away with the washing however. The thread is a silver coating on a synthetic fibre, so of course, washing will degrade the integrity of the silver, over time.