I'd like to disable spelling auto-correct in Safari!
Using OS X 10.7 or higher, there are at least two ways to disable automatic spelling correction: globally, and on an individual app basis. Disabling autocorrect can be useful for those who often need to spell out things that would come up as incorrect in the dictionary, such as HTML CSS style editors who need to use "center" instead of the autocorrected "centre".
To disable automatic spelling correction globally (at least across apps that use OS X's dictionary):
- click on the apple icon on the top-left of the screen
- click on System Preferences ...
- click on Language & Text
- click on the Text tab
- uncheck Correct spelling automatically
To disable automatic spelling correction in Safari:
- first click on any text field where you can type (otherwise the relevant menu option will be greyed out)
- in the menu on the top of the screen, click Edit -> Spelling and Grammar
- if checked, uncheck Correct Spelling Automatically
Both of these worked using Safari 6.0.2 under OS X 10.7 and 10.8. Your mileage may vary across other versions of OS X and Safari.