Recently the colors on my Iphone 3g have started looking inverted or negative, I havent dropped my phone or had it damaged, but I cant seem to make it go back to normal. i have also done some research on this and found out that you can purposely do this through accessibility but my phone doesnt give me that option....HELP!
You need to look in General Settings. Scroll down to Accessibility. In there, you have a switch to turn White on Black on/off. That's the thing that reverses the colours on the iPhone.
Is your iPhone jailbroken?