Yeah, early next year Borders is relaunching borders.com as its own e-commerce site, and will supposedly start selling Sony books there. The article I found that stated all this was from September, so the timing may no longer be accurate. I did notice, however, that within the first week of owning my 505 the Sony Connect software added a Borders logo to the top of the store.
Here's the article about Borders and Sony, and the new borders.com:
http://www.publishersweekly.com/article/CA6480000.html
About 10 years ago I had a large number of friends working for Borders, and they all lamented how poorly borders.com was doing. A few years later they had closed up shop and just slapped their name on an amazon.com store. I'm not exactly holding my breath that borders.com will survive this time around.