This morning in Europe, Sony Entertainment Network webstore quietly launched, which now you can use your on PC to buy PSN content For the most part it is accessible in Europe such as the U.K., but it's not available yet in the North American Side. A Sony Computer Entertainment UK rep told Joystiq, "We are testing a new web store, which we look forward to announcing and launching to the PlayStation/Sony community shortly."
The SEN store offers a nice redesigned PS Store. It has a nice GUI in which content can be easily filtered by platforms, genre, price etc. It closely resembles Xbox.com webstore except purchases can't be automatically downloaded.
Sony had converted PSN accounts into SEN ones earlier this year, to structure themselves more properly as one giant corporation instead of many severed parts. This move makes it a lot easier to buy content