Athlete's foot is a very common name for a skin infection caused by fungus. It appears between the toes and on the soles of the feet. Serious cases may involve cracking, peeling or bleeding skin.
Athlete's foot can be contagious and spread fairly easily from one person to another (via spores in wet conditions) or one area to another (by sharing shoes). If you are experiencing any of these symptoms make sure you stop touching your feet and avoid moist areas with communal footwear until you have been treated.