Aquí el formulario:
Código PHP:
<form action="pruebas.php" method="POST">
<input type='checkbox' name="area" value="area1" selected>area1
<input type='checkbox' name="area" value="area2" selected>area2
<input type='checkbox' name="area" value="area3" selected>area3
<input type='checkbox' name="area" value="area4" selected>area4
<input type="submit" value="Enviar datos" >
</form>
Código PHP:
$areas=$_POST["area"];
for ($i=0;$i<count($areas);$i++)
{
echo "<br> area " . $i . ": " . $areas[$i];
}