I'm collecting here some of the more interesting items I've found about the continuing evolution of e-readers:
Sony opens its e-reader to 'outside' publishers (allowing for a greater selection of books on its device).
Good critical feedback on Sony Reader.
Prototype of a more flexible reader (Plastic Logic's more flexible device has an 8.5 X 11 display, which allows for a pop-up, touch-sensitive keyboard; and since it loads Office documents easily, it might take over some of the functions of a laptop -- and it will still work after you beat it with a shoe).
Dual-display prototype from Berkeley and Maryland researchers (you can hold it like a book, seeing two pages at once, and the pages can be from different documents; or you can fold it to see just one page at a time).
Update (Sept. 6): New versions of the Sony and Kindle readers will soon hit the market.