As a tribute to Jack Vance, Open Books has just added a dozen DRM-free ebooks from amazon and the official Jack Vance website.
Check it out.
PS: please let me know if the links to the official vance website pages selling the ebooks allow you to buy it if you are from the USA. They don't if you are in India, so i need the feedback.
Also note that not all Jack Vance ebooks on amazon are DRM-free. Look for "Simultaneous Device Usage" under "Product Details" and if it is set to "Unlimited" only then the book is DRM-free.
However all the ebooks on the official Jack Vance website are DRM-free, atleast that is what they say.