Any yarn that yields a good drape will be fine. Gauge is not important.
The shawl was designed especially for Rebel Yarn.
The kit (yarn + pattern) is available at Rebel Yarn. Untill January 1, 2013, you can by the kit at 10 % discount (please use the code Kuduja). If you want to purchase the pattern only, you can download it from my Ravelry shop.