What's a girl (or guy) to wear??

These days the protocol for wedding attire is much more of a grey area than it used to be. From formal mountain weddings to casual beach weddings to black tie affairs, who's to know how to dress and more importantly how to let you guests know what to wear??!!

I come across this question all of the time when designing invitations, and I found this bit of information that I found helpful in defining the appropriate attire:

• Black tie or black tie optional: this is a cue to your guests that the men should be in a tuxedo or dark suite, and the ladies should wear evening gown or formal dress.
•  
• Semi Formal: this indicates that the men should be in a suit or jacket and the ladies should be in an elegant dress or dressy suit.
•  
• Cocktail Attire: indicates that the men should wear a dark suit and the ladies a pretty cocktail dress.
•  
• Casual Attire: indicates that the men should wear nice pants and a collared shirt and the ladies may wear a simple dress or nice pants. 

And if this does not get the attire across, then I also suggest a wedding website that describes the attire in greater detail. And lastly, good old word of mouth!