Yes I Can!

iPhone Explorer app Change iPhone App Icons Without Jailbreaking

If you have a number of apps you like but hate their icon, and don’t want to jailbreak your device just to change default app icons, you can now do so with the help of the instructions below, c/o UNEASYsilence.
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You will need the iPhone Explorer app, which is free for Macs and PCs, to navigate through the iOS filesystem and make the necessary changes. You wont, unfortunately, be able to change any of the default Apple apps, or official apps available through the App Store, such as Remote.app.

1. Navigate (using iPhone Explorer) to

(phone name) /Apps/(appname)/(appname.app), For example, it will look something like Johnny’sAppleiPhone/Apps/Twitter/Twitter.app, if you’re changing the Twitter app icon.

2. Rename your new icon (must be a .PNG file, size 114×114, 72 PPI “icon@2x.png” (case-sensitive). For 3G and 3GS users, the icon will be titled “icon.png” and the new version should be sized 57 x 57.

(back up the old icon if you might want to restore it in the future)

3. Drag your replacement icon to that folder in iPhone Explorer

Now all you have to do is reboot your device. Don’t worry about the rounded edges of the app icons, as iOS automagically does it for you.