Here's a great post from Ragan.com on the misuse – with tips on the correct use – of quotation marks.
This form of punctuation is sometimes misunderstood and often overused. Here’s what you should know.
Do you find yourself using air quotes? Be honest. How about in your writing? Are your sentences peppered with single or double quotation marks? Are you sure you’re using them correctly?
Quotation mark abuse is so rampant, it begat a popular website, The “Blog” of “Unnecessary” Quotation Marks, documenting their often confusing, but always funny, misuses.
Read the post for tips on how you should use quotation marks, but PLEASE take a few minutes to visit The "Blog of "Unnecessary" Quotation Marks. Seriously good stuff!