It looks like Canada’s Rogers and Fido want to shift a few iPhone 3G S handsets on launch day, as appleinsider reports Rogers and Fido promise heavy discounts for iPhone 3G owners who upgrade to the iPhone 3G S.

Although the Rogers and Fido discount does depend on just when you purchased your iPhone 3G and how much they fork out on monthly service. The best benefit goes to those who gained their iPhone 3G before September 30th with a minimum $100 per month service plan as they will gain full subsidy giving them the iPhone 3G S 16GB for $199 and 32GB for $299.

If you spend under $100 per month but purchased the handset before the end of 08 there is a partial discount available whereby the iPhone 3G S 16GB costs $449 and 32GB costs$549. Fido customers can also use their FidoDollars towards the cost of the iPhone 3G S.