I just received this email yesterday. I want to encourage people that Apple don’t send out emails like this – it is a scam.
One way that you can tell this is to look at the link in the email and see that it does not actually go to apple.com. It looks like it goes to apple.com but if you have a look in the top of the browser window after you click on it, it will be a different address.
If you are unsure about anything like this your best bet is to ring Apple on their advertised number – that way you are sure to actually be talking to Apple.
(In Australia their number is 133 622 or in the USA 800 275 2273. You can verify this from Apple’s website.)