Does Google have a tool for suggesting misspellings for your AdWords campaign? Nope! Instead, a Google rep, AdWordsPro Sarah, recommends someone else.
Can you guess who?
However, you also can try to use Google's keyword tool; it just needs to have sufficient search volume to be recorded:
If the misspelling or typo of a keyword has a consistent amount of traffic, you will see these results in the AdWords Keyword Tool. All you would need to do is type in the correct keyword and then sort through the results.
Forum discussion continues at Google Groups.