Tons of resources for getting started with Arduino and troubleshooting problems along the way.
Here are some great websites for buying supplies, please let me know if you have more suggestions.
*Note* most of theses stores ship internationally but it may cost more.
Here are some great sites for further wearable/DIY inspiration !
Hack A Day
AdaFruit Wearable Blog
Kobakant DIY Wearable Blog
Lily Pad, Arduino specifically for wearables
Soft Circuit Instructables, a collection edited by Laura Khalil
All About Circuits Arduino Projects