A skin fade is a relatively new style of haircut and is often chosen by men who want to keep their hair on the top of their head but a lot shorted on the sides. The skin fade is done by the barber carefully shaving the bottom of the hair line almost completely smooth and then gradually increasing the length as they move towards the top of the head. This gives the effect of the hair fading out as you move towards the neck, hence the name skin fade.
If you have never had this cut done before then you may be a little nervous as if not done correctly it can end up looking a bit odd and if the fading is not done gradually you may end up with abrupt lines.
When looking for a barber, make sure they are experienced in skin fades and ideally try and see some of their pervious work. This will allow you to see how good they are help you decide if you want to go to them or not. Often more youthful, trendy barbers are the ones who are most experienced in these sorts of styles and will most likely do a good job.