The Lord of the Rings,by J.R.R. Tolkien (with credit given to Christopher Tolkien on the Kindle Edition), has arrived in ebook form. You can purchase the The Trilogy ($15.94) as a single volume or each book individually ($9.99 each):
The Fellowship of the Ring
The Two Towers
The Return of the King
You can also pick up The Hobbit ($7.99) and The Children of Hurin ($9.99), the earliest and latest works Tolkien published (Hurin, of course, was a posthumous publication and greatly edited by Christopher). All we need now is the History of Middle-Earth (5 volumes) and The History of The Lord of the Rings (4 volumes) and the Later Silmarillion (2 volumes), but we can wait (after all, it'll take a day or two to read thru what we have so far).
For those who don't have a Kindle (and those who do, that want a copy on their desktop), you can also get these at Fictionwise. Even better, thru April 26, they are giving a 100% micropay rebate on all the Tolkien titles, if paid for via credit card or paypal. That credit can be used on any purchases (but not in conjunction with high rebate offers) for any other books in the store. Although their secure Mobipocket titles won't work on Kindle, due to DRM, almost all the multi-format titles will (just be sure that mobi/prc is an option on the title; it is for most I've checked).