The For Strength of Youth pamphlet has a great overview of dress standrads of the church.  
 
Overall LDS members should never wear clothing that goes above the knee, or exposes the naval, back, breasts,or shoulders this standard applies to both men and women.  
 
The sole exception is swimwear men are ecouraged to wear appropriate swim trunks and women are encouraged to wear one piece bathing suits, when done swimming modest attire should be changed into or worn over the swim suit.