Here is a simple function that opens a file, reads it in a line at a time, and prints the output to the screen. The nl2br statement in the function will convert the newline characters ("\n" or "\r\n" depending on your OS) to HTML breaks, "<br>".

<?php
/*******************************************************************
* Function: ReadAFile($filename)
* Input   : a valid filename as a string
* Output  : prints the contents of the file to the screen
* Returns : nothing
********************************************************************/
function ReadAFile($filename)
{
  //open the file for reading
  $fp=fopen($filename,"r");
  //get a line, store it in the
  //$line variable
  while($line=fgets($fp)) {
    print nl2br($line);
  }
  //close the file pointer
  fclose($fp);  
}
?>