Here are 3 web sites that answer the first part of your question.

http://beauty.about.com/od/hairremoval/a/laserhair.htm

http://www.body4real.co.uk/pages.php?pagecode=Laser_Hair_Removal&js=y

http://health.learninginfo.org/laser_hair_treatment.htm

Disadvantages:

• At least 4-6 treatments will be needed;
• The effectiveness depends on skin’s color It’s still impossible to avoid the risk of skin burn;
• It’s quite expensive.

Laser hair removal is not suitable, if you have:

• Skin diseases;
• Diabetes;
• Ontological skin diseases;
• Cardiovascular system diseases;
• Infection diseases;
• Pregnancy;
• Very dark or newly sunburn;
• Your age is under 17.