Radio Shack (Stock Quote: RSH) announced via its Twitter account that not only will it sell the iPhone 4 on the June 24 launch day, but that it will take trade-ins on iPhone 3G and 3GS models.

Radio Shack said stores will offer a $100 trade-in for the iPhone 3G and a $200 trade-in for the iPhone 3GS. (This is part of the retailer’s pre-existing trade-in program where customers can exchange electronic devices for Radio Shack gift cards.) The iPhone 4 will cost $199 for the 16 GB model and $299 for the 32 GB model for new customers who sign on to a 2-year contract with AT&T (Stock Quote: T). 

“Essentially, a 3GS in good condition would get you a 16G iPhone4 for nada if you're upgrade eligible,” Radio Shack said via Tweet. 

The Shack said pre-orders for the latest iPhone start June 15. Interested buyers will be required to make a $50 deposit in order to reserve the gadget. 

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While Radio Shack does currently carry the iPhone 3G, this is the first time it will have Apple’s latest version on its launch day. According to Engadget, Best Buy (Stock Quote: BBY ), which had both the iPad and the iPhone 3GS on launch day, is also rumored to be carrying the iPhone 4 on June 24. Of course, you can get definitely get your new iPhone at a local Apple store.  You just might have to wait a little.

For more information on Apple’s latest smartphone, check out MainStreet’s article The iPhone 4: What’s New? Or find out the iPhone’s dirty little secret.

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