CakePHP has builtin functions in it's HTML Helper class to easily generate dropdown lists for date selection: dayOptionTag(), monthOptionTag(), yearOptionTag() and finally dateTimeOptionTag(). The latter is very handy for quickly constructing registration pages. By default the starting year for this tag is 1947 (in version 1.1.11.4064) that you cannot directly change, however by modifying the third parameter of yearOptionTag() - which dateTimeOptionTag() relies on - you can change this default behaviour. Alas you have to make changes in the framework, namely in the HTMl Helper class to do this. The source at issue is:
[...]/cake/libs/view/helpers/html.phpLook for the function dateTimeOptionTag(), and specifically this piece of code:
switch($dateFormat) {
    case 'DMY': // so uses the new selex
        $opt = $this->dayOptionTag($tagName, null, $day, $selectDayAttr, $optionAttr, $showEmpty) . '-' .
        $this->monthOptionTag($tagName, null, $month, $selectMonthAttr, $optionAttr, $showEmpty) . '-' . $this->yearOptionTag($tagName, null, null, null, $year, $selectYearAttr, $optionAttr, $showEmpty);
    break;
    case 'MDY':
        $opt = $this->monthOptionTag($tagName, null, $month, $selectMonthAttr, $optionAttr, $showEmpty) . '-' .
        $this->dayOptionTag($tagName, null, $day, $selectDayAttr, $optionAttr, $showEmpty) . '-' . $this->yearOptionTag($tagName, null, null, null, $year, $selectYearAttr, $optionAttr, $showEmpty);
    break;
    case 'YMD':
        $opt = $this->yearOptionTag($tagName, null, null, null, $year, $selectYearAttr, $optionAttr, $showEmpty) . '-' .
        $this->monthOptionTag($tagName, null, $month, $selectMonthAttr, $optionAttr, $showEmpty) . '-' .
        $this->dayOptionTag($tagName, null, $day, $selectDayAttr, $optionAttr, $showEmpty);
    break;
    case 'Y':
        $opt = $this->yearOptionTag($tagName, null, null, null, $selected, $selectYearAttr, $optionAttr, $showEmpty);
    break;
    case 'NONE':
    default:
        $opt = '';
    break;
}

In the above code you can change the starting year by replacing the third parameters of yearOptionTag() calls with a number you wish (instead of leaving it being null). This is easy, but implicates a bigger problem. Since you need to modify the framework itself, you cannot store CakePHP in and include from a single folder, but you have to copy the changed source to your actual project folder (and every project folder that need custom starting year). Something must be done about this in future versions of CakePHP. Otherwise it is a nifty framework to work with.