[Plugin: HTTPS for WordPress] Incomplete checking of https

how about this:

function isSSL()
{
   if(!empty($_SERVER['HTTPS']){ return true; }
   else{ return false; }
}

I suppose if you really wanted to you could check the server port.

function isSSL()
{
   if(!empty($_SERVER['HTTPS'])||$_SERVER['SERVER_PORT']==443)
   { return true; }
   else{ return false; }
}

I always check if $_SERVER[‘HTTPS’] is not empty. The PHP Documentation says that $_SERVER[‘HTTPS’] is, “Set to a non-empty value if the script was queried through the HTTPS protocol.”