How can I detect if my website is vulnerable to POODLE?
You can use Nmap to check if your site is vulnerable to POODLE by supporting SSLv3.
nmap --script ssl-enum-ciphers -p 443 www.example.org
If it is and you are running Apache you can disable SSLv3 in your virtual host by add the line
SSLProtocol All -SSLv2 -SSLv3
For more information and Nginx and other services please see http://askubuntu.com/questions/537196/how-do-i-patch-workaround-sslv3-poodle-vulnerability-cve-2014-3566.