Just incase you decide you'd like to change it later, here's what you'd do...
Open myvbindex.php and look for this line:
PHP Code:
$calendarbits.="<td bgcolor=\"{ firstaltcolor}\"><smallfont color=\"{ caldaycolor}\">$daylink</font></td>";
(Be sure to remove the space in front of { firstaltcolor} and { caldaycolor} when you search for that)
Then you'd just change { firstaltcolor} to whatever you'd like it to be, and if you'd like to change the font color you'd just change the { caldaycolor}.