This site is put together by Doc Scott (or his dog).  It has an amusing tone and easy to follow explanations of grammar rules.  Doc Scott only covers the basics here, but offers a good self-quiz.

Big Dog's Grammar: A Bare Bones Guide to English. http://aliscot.com/bigdog/dangling.htm

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This page is from Dr. Charles Darling's Guide to Grammar and Writing sponsored by the Capital Community College Foundation.  The discussion of dangling modifiers is solid, with examples of "confusing" sentences and "repair work."   The site also offers 2 different quizzes on modifier placement and a link to a great resource page on creating sentence variety through the addition of different types of modifiers.

"Modifier Placement," Guide to Grammar and Writing. Dr. Charles Darling. Capital Community College Foundation.  http://grammar.ccc.commnet.edu/grammar/modifiers.htm#danglers

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Grammar Girl's podcasts on grammar are easy to understand and they are often fun, too.  This podcast on misplaced modifiers is to the point, covering the most common situations that lead to misplaced modifiers and quick tips on how to correct these mistakes.

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Towson University's Online Writing Support Center has prepared a great web page on misplaced modifiers.  Lots of great graphic detail clearly illustrates how modifiers work in a sentence, and how misplacement corrupts the logic of the sentence.

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