I'm making a PHP script which makes a list of first and last names, taken from a form. And then saves it to a .txt file.
As several people is just placing one name after another instead of using line breaks.
I need to make a line break every 2 words manually.

This is what I got so far:

PHP Code:
$dia=$HTTP_POST_VARS['dia'];
$invitados=$HTTP_POST_VARS['invitados'
$clean 
ereg_replace("[^A-Za-z \n]"""$invitados); //clean
$lowercase strtolower($clean); //remove caps
$text ucwords($lowercase); //capitalize
$lista //here I should need the code that modifies the $text string and makes it a list

//Which list?
if ( ($dia) == "Jueves" ) {
$file "ListaJueves.txt";
} else if ( (
$dia) == "Viernes" ) {
$file "ListaViernes.txt";
} else if ( (
$dia) == "Sabado" ) {
$file "ListaSabado.txt";
} else if ( (
$dia) == "Feriado" ) {
$file "ListaFeriados.txt";
} else { exit; }

//Write the file
$fh fopen($file'a') or die("cant open file");
fwrite($fh"\n".$lista);
fclose($fh); 
As you can see, as it gets the $invitados string it gets formatted and removes non-Alphabetic characters, but then I would need to make my .txt list to look like a list.

Now for the real question:
How do I make a new line after every two words from a block of text?

It should make this:
Gonzalo Novoa Gerardo Gaudio, Norma Lean, Carlos Lobieta
to look like this
Gonzalo Novoa
Gerardo Gaudio
Norma Lean
Carlos Lobieta
Please note that it should replace the space after "Novoa" in the example, as well as the commas.
There's some annoying people who separates names with more characters than only commas or no comma at all.
Adding the linebreak after every two words is my main concern.