Been working with a label recently and they have started to use a cool online payment mechanic called topspin. The tool allows you to embed widgets and email promotions to your audience. You can also blog prmotions via twitter and facebook. There is even a means to use facebook to host a shop and cross sell products.
The biggest feature for me is the VIP level access for certain products. There is the possibility to create levels of VIP access to grant access to those who have paid for their content or subscribed to a yearly fee for exclusive offers/discounts. Topspinmedia.com.
Here’s an example widget for a recent free release from Turnstilemusic.net.