This would be your "More Info" button:
<a href="form.php?id=Vegas"><img src="more_info.gif" /></a>
On "form.php" you would put:
<?php $vacation = $_GET['id']; ?>
Then use something like <?php echo "yourhtml".$vacation."morehtml"; ?>, to echo the whole form and put the variable $vacation value where you want it to be. Or, simply use <?php echo $vacation; ?> inline in your form to place the variable value in the proper place.
That's a simple example. If (like above) I was using an "a" link button, I'd probably use sprites and use a span for my text link to get more SEO out of it. An alternative would be to use a "hidden" form like this:
<form name="info" action="form.php" method="post">
<input type="hidden" name="more_info" value="Vegas">
<input type="submit" value="More Info">
</form>
Then on "form.php":
<?php $vacation = $_POST['more_info']; ?>
And so on. The second method would enable you to pass the variable onto "form.php" without showing it in the url of "form.php". Again, a simple example. Don't forget to include the proper security measures.