PHP: two column lists lay out

PHP: two column lists lay out

I'm listing some movies in my web so the user can choose the best movie.
I'm classifying them by genre.
But the lists under each genre are too long and I want to make two columns
of titles.
The number of movies in each column will depend of the genre.
So my code is like this now:
$i = 1;
echo "<ul>";
foreach($arrayMovies as $k=>$v)
{
echo "<li><input type=\"checkbox\" id=\"flat-$i\" name=\"$genre-$i\"
value=\"$k\">
<label for=\"flat-$i\">$v</label></li>";
$i++;
}
echo "</ul>";
This code is showing the long list, something like this for drama:
Forest Gump
The Hours
Mullholand Drive
Titanic
..
..
Let's say that for the drama genre I need two titles per column:
<ul>
<li> Forest Gump</li>
<li> The Hours</li>
</ul>
<ul>
<li> Mullholand Drive</li>
<li> Titanic</li>
</ul>
How can achieve this with my code??
The second column I can achieve by using css, I just need a new <ul> after
two titles.
Please notice that the number two in -two titles per column- is a dynamic
number*
*I'll count how many rows per title each genre has to get a total number
and then I'll do half of it to get the number of titles per column (the
number of titles in each genre is even)
Thanks very much!