Recently Microsoft Celebrated their 5th Aniversary of XBL with the 5IVE promotional downloads and giveaways. Also there were rummors about Microsoft giving away 500 points for free to XBL subscribers with accounts since 2002. This rumors are true. However, if you are just sitting around waiting for your points to be credited to your account... The points won't just appear, for a VERY limited time you will have the chance to register for this points. Below I have posted the detalis as listed on teamxbox.com

Details:

Microsoft is celebrating the fifth anniversary of Xbox Live in a big way. It has released Carcassonne for free and it is also giving away 500 Microsoft Points to every active member who joined the service in 2002. If you were wondering how to get those precious MS Points, we have the answer.

To claim your 500 Microsoft Points, all you have to do is register on this web site using your Windows Live ID associated to your gamertag. You can register until midnight (Pacific Time) on November 29, 2007, and after you do so, you will receive an e-mail with a 25-digit code that lets you to activate your Microsoft Points through your Xbox 360 console. Don't expect that email to arrive instantly as the deadline for that email is December 21, 2007.

It is also worth mentioning that these 500 Microsoft Points expire on June 30, 2008, but we are sure you'll spend them way before that date.