The curly updo hair style looks great for a prom hair style.  Leave out a few wispy bangs and strands.  To create this hair style, you will first need to pull back most of the hair and create a base. Next you will pin small sections of curls directly into the base.  This is a more complicated hair style that may require the help of a hair stylist. 
 

Also you would want to schedule a trial run with your hair stylist to make sure that this style will stay put for a night of dancing.  Having a lot of pins in your hair can become annoying after several hours and you should keep this in mind when deciding on this style.

Wavy partial updos also work well for the formal hair style.  To create this style, apply a curl-enhancing cream through hair.  Blow dry the hair using a diffuser attachment.  Add all over curls using a curling iron.  If you have time, you can try to put small braids all over the head and allow the hair to dry naturally.  This is a great way to create all over waves without any hair appliance.  However, this method will require a lot of drying time.

This curly, medium hair style also has great potential for a prom hair style.  Add all over corkscrew-like curls by placing small sections of hair in a curling iron and turning the curling iron in a vertical position for several seconds.  Always allow the hair to cool completely before trying to shape and position the curls.  If you touch the hair when it is still hot, you may loose all the curls that you just worked hard to put in.

Always spray a holding hair spray to help keep the style in place.