You can use:
fopen, fwrite and fread to store form data in a text file. The fopen(filename, a) function opens the file for writing at the end of the file (apend mode) if the file does not exist then it gets created.
$filehandle = fopen("addresses.txt", "a");
fwrite ($filehandle ,$form_field );
fclose ($filehandle);
to read the file use:
$filename = "addresses.txt";
$filehandle = fopen ($filename, "r");
$contents = fread ($filehandle, filesize ($filename));
fclose ($filehandle);
echo $contents;
HTH
Steve