Even though there is nothing much on that, they are saying that they are in the final talks with Apple. The URL to the page is http://info.singtel.com/personal/communication/mobile/mobile-phones/iphone4.

iPhone 4 availability: SingTel is keen to bring the new iPhone 4 to customers and we are in the final stages of discussions with Apple. SingTel plans to make the new iPhone the most affordable and compelling with breakthrough mobile apps and value-added services. We will be updating customers on the latest details. We thank our customers for their patience and support.

PS: SingTel sent a iPhone 3GS teaser last year on 2nd July 2009.

*UPDATE* SingTel took down the link.
*UPDATE 2* The link is back up again.

Official Site: SingTel iPhone 4
Source: TechieLobang: Singtel is Ready for iPhone 4?