You can do two things if the iPhone auto-correct bothers you: turn it off or edit it. Turning auto-correct off is easy to do, while actually editing what gets auto-corrected requires a little more work. Depending upon the frequency with which you interact with auto-correct, it may be better to turn it off, but if you want the spelling backup, manual editing may be preferable.
Click "Settings" on your iPhone to turn off auto-correct. Click "General." Click "Keyboard." Go to "Auto-Correction" and click the "On" button to change it to "Off." Note: this will also turn off "Check Spelling."
Launch the Safari browser app on your iPhone to edit auto-correct. Type the word you would like to edit into the Google search bar in Safari. Make sure you correct the spelling of recommended words.
Update the auto-correct dictionary by correcting recommended words in the Google Search in the Safari app. The file that gets overwritten is: private/var/mobile/Library/Keyboard/dynamic-text.dat