Check your server meets the Magento Requirements

Create a php file, paste in the contents below and upload to the server - then just visit that file in your browser for the results.

Or just download from magento and upload http://www.magentocommerce.com/_media/magento-check.zip

<?php
extension_check(array( 
'curl',
'dom', 
'gd', 
'hash',
'iconv',
'mcrypt',
'pcre', 
'pdo', 
'pdo_mysql', 
'simplexml'
));

function extension_check($extensions) {
$fail = '';
$pass = '';

if(version_compare(phpversion(), '5.2.0', '<')) {
    $fail .= '<li>You need<strong> PHP 5.2.0</strong> (or greater)</li>';
}
else {
    $pass .='<li>You have<strong> PHP 5.2.0</strong> (or greater)</li>';
}

if(!ini_get('safe_mode')) {
    $pass .='<li>Safe Mode is <strong>off</strong></li>';
    preg_match('/[0-9]\.[0-9]+\.[0-9]+/', shell_exec('mysql -V'), $version);

    if(version_compare($version[0], '4.1.20', '<')) {
        $fail .= '<li>You need<strong> MySQL 4.1.20</strong> (or greater)</li>';
    }
    else {
        $pass .='<li>You have<strong> MySQL 4.1.20</strong> (or greater)</li>';
    }
}
else { $fail .= '<li>Safe Mode is <strong>on</strong></li>';  }

foreach($extensions as $extension) {
    if(!extension_loaded($extension)) {
        $fail .= '<li> You are missing the <strong>'.$extension.'</strong> extension</li>';
    }
    else{   $pass .= '<li>You have the <strong>'.$extension.'</strong> extension</li>';
    }
}

if($fail) {
    echo '<p><strong>Your server does not meet the following requirements in order to      install Magento.</strong>';
    echo '<br>The following requirements failed, please contact your hosting provider in order to receive assistance with meeting the system requirements for Magento:';
    echo '<ul>'.$fail.'</ul></p>';
    echo 'The following requirements were successfully met:';
    echo '<ul>'.$pass.'</ul>';
} else {
    echo '<p><strong>Congratulations!</strong> Your server meets the requirements for Magento.</p>';
    echo '<ul>'.$pass.'</ul>';

}
}
?>