I know that this is an old topic, but I was looking to see if anyone else here had some tips about this topic, and I see that no one has posted these sources yet. -I hope this falls under the “being relevant” exception according to the third general forum rule. ^^; If I am wrong, please let me know and my apologies.- I have some legal sources of raw digital manga and light novels that I use and thought anyone else who stumbles on this thread might find handy. I also like to know the level of difficulty before buying a book, @クレイグ. :)

If you want read chapters of (newer) manga for free.
http://www.famitsu.com/comic_clear/ -has a number of titles; some of which have whole volumes available!
http://comic-walker.com/ -is from Kadokawa and features the latest chapter of Kadokawa’s titles.
http://www.s-manga.net/ -is the digital portal for Shueisha’s manga and has previews of the latest volumes available for viewing.

If you want to browse before buying in (light) novels as well as manga, and/or if you would like to buy them as e-books. I can recommend the following.

http://bookwalker.jp/ -Is Kadokawa’s e-book store. You can preview a title, some 10-20 pages. Unfortunately, not all of their titles are available for viewing and purchase outside of Japan, but in my experience the majority of them are available. They also accept Paypal, and every month they have a collection of free titles http://bookwalker.jp/new/free/; and they have an expanding global/English version of their site that sells English-translated digital manga http://global.bookwalker.jp/. Their English reader app works just fine with their Japanese content as well, so you can use just one account for both sites.

http://www.ebookjapan.jp/ -I haven’t yet had the opportunity to purchase from this site, but this is another one that sells Japanese ebooks worldwide. -When signing up and they ask for your address, just chose 海外 at the bottom of the drop-down list and you should be good to go.- They have an even larger selection than Bookwalker, and from what I can tell so far don’t seem to have as much restriction in selling certain titles to outside of Japan. They also allow for previewing almost all of their offerings and offer free books http://www.ebookjapan.jp/ebj/freebooks/index.asp

As a last disclaimer, of course, I am in no way affiliated with any of these sites. ;)
Happy reading to anyone this helps!

Does anyone else know of a good site to enjoy legal, Japanese-language digital books/manga? I really prefer to not have to deal with the hassle of shipping when I can avoid it.