The new update improves system performance, and real money transactions
An update is on the works for the Xbox 360 that smooths out the console's performance and enables you to buy products with real cash instead of banana bucks -- and if you want to test it out, you can sign up directly on your Xbox 360's home hub located on your dashboard.
It's not an altogether exciting update, but according to Major Nelson "space is limited," so once the quota is filled they'll close off access. If you want to get in, now is probably a great time to boot up your 360 and register. Personally I think I can wait, but I'm really excited for the elimination of Microsoft Points in general.
Xbox Live Update [Major Nelson]