You'd have to try something like this:
<input type="text" id="title" name="title" /><br />
<input type="file" id="file_upload" name="file_upload" />
<div id="uploader_message"></div>
<a href="javascript:$('#file_upload').uploadifyUpload();">Upload Files</a>

$('#file_upload').uploadify({
'uploader' : 'uploadify/uploadify.swf',
'script' : 'uploadify/uploadify.php',
'scriptData' : {'title' : $('#title').val()}
});
With $('#title').val() you can retrieve the value of the text-field and place as scriptData which you can access in uploadify.php with:
$_POST['title']