The white version of the phone is available in China only, at least for now. Speaking of which, the Xiaomi Redmi will initially just support the TD-SCDMA proprietary 3G pipeline, belonging to China Mobile.
When the original black version was offered with WCDMA connectivity for China Unicom back in November, 100,000 units sold in just 4 minutes. With sales like that, you can expect a white WCDMA version of the Xiaomi Redmi to be available in the not too distant future. The price of the white Xiaomi Redmi for China Mobile is 699 Yuan ($113 USD).
Xiaomi Redmi is available in white
source: CnBeta.com (translated), gizchina via IntoMobile