You can't. Not with a credit card, at least. You can purchase a retail copy from a retailer in the US who will ship it to you or have someone in the US purchase it and send you the key from inside the package. You can the activate a subscription with that key for a year.
Be sure to read the announcement -
Announcement 11/18/08 - you may want to forego purchasing a subscription.
-steve
In which countries and languages is Windows Live OneCare available?
The Windows Live OneCare subscription service is available in the following countries and languages: Australia (English), Austria (German), Belgium (Dutch, French), Brazil (Portuguese), Canada (English, French), France (French), Germany (German), Hong Kong (English), Ireland (English), India (English), Italy (Italian), Japan (Japanese), Mexico (Spanish), Netherlands (Dutch), New Zealand (English), Singapore (English), Spain (Spanish), Switzerland (French, German), United Kingdom (English), United States (English, Spanish).
Pasted from <http://onecare.live.com/standard/en-us/faq.htm>
Microsoft MVP Windows Live / Windows Live OneCare & Live Mesh Forum Moderator
