Not due out for retail until early December....
http://www.bestbuy.com/site/olspage.jsp?skuId=8008988&type=product&productCategoryId=pcmcat103600050009&id=1156203388826
...or you can call Nintendo...
In fact, the only way to secure component cables at this point in time is to call 1-800-255-3700 and order them by phone. The cost of the cables themselves is $29.95 plus tax and shipping fees. Standard shipping is only an additional $5, but it may not be the most reliable way to ensure that you will get the cables at launch. Two levels of expedited shipping are available: 3-5 business days costs $7 and 2 days costs $13. Prior to writing this, we called and ordered the cables for ourselves, so we can verify that this is, in fact, quite true and quite convenient.
http://wii.ign.com/articles/746/746085p1.html