it's generally bad practice to have several fields with the same name, unless it's a radio button group or similar.
but, if you have to, then name the fields with a [] at the end - ie
<INPUT TYPE="text" NAME="field[]" VALUE="field1">
<INPUT TYPE="text" NAME="field[]" VALUE="field2">
then within the $_POST global will be an array $field containing values "field1", "field2" etc
hope this helps
adam