How do I create a self signed SSL certificate to use while testing a web app

How do I create a self-signed SSL Certificate for testing purposes?

from http://httpd.apache.org/docs/2.0/ssl/ssl_faq.html#selfcert:

1. Make sure OpenSSL is installed and in your PATH.

2. Run the following command, to create server.key and server.crt files:

   openssl req -new -x509 -nodes -out server.crt -keyout server.key
   

   These can be used as follows in your httpd.conf file:

   SSLCertificateFile    /path/to/this/server.crt
   SSLCertificateKeyFile /path/to/this/server.key
   

3. It is important that you are aware that this server.key does not have any passphrase. To add a passphrase to the key, you should run the following command, and enter & verify the passphrase as requested.

   openssl rsa -des3 -in server.key -out server.key.new
   mv server.key.new server.key
   

   Please backup the server.key file, and the passphrase you entered, in a secure location.