I was wondering if there were any other authors besides Yu Wo who have given their fans permission to translate their work.

Yes:

Quote from barbapapa

I've exchanged some tweets with some authors, but the most contact I have with Toyokazu Matsunaga. I translate Paperakyu, fully condoned by him.

Matsunaga actually has a link to the translations for the first couple chapters on the bottom of his site for the series.

Sato Shuho made Say Hello to Black Jack free to download on his website. English translations were contributed by fans.

Thank you!

I think NAM Hee Sung has given full permission to translate his work The Legendary Moonlight Sculptor (Novel).

[img]http://media.tumblr.com/e43f35cfdd762cc666571a6dd0f163d5/tumblr_inline_mhbel8Cy8V1qz4rgp.gif[/img]

Quote from strixflash

I think NAM Hee Sung has given full permission to translate his work The Legendary Moonlight Sculptor (Novel).

Nope. He gave permission for the first 5 volumes (which i believe was licensed but failed) and said he'd decide on the rest later.

Quote from ListeningDaisy

I was wondering if there were any other authors besides Yu Wo who have given their fans permission to translate their work.

That was pretty cool, but you should remember that her situation was kinda unique as half-prince started off as novels she wrote and uploaded to the internet for free.

the guys behind The Breaker were kinda pissed at first about scanlations but when they went to France some of the fans there spoke to them about it and they became more understanding. Not that they said something like 'I approve' but they were...intrigued.

Supreme Cream Scanlations got permission from Lee Jun to scanlate The Friendly Winter. You can read about it here at the end of the chapter. http://www.batoto.net/read/_/159546/the-friendly-winter_v2_ch64_by_supreme-cream-scanlations

I was also wondering if there were any groups that did what Odd Squad Scanlations did with Cheese In the Trap.

Nakama got permission from OKADAYA Tetuzoh for some of her works (quite some time ago so I don't know how valid that is now).
And i think something similar happened between Liquid Passion and Miyamoto Kano but i can't confirm that as i've read about this on 3rd party site.

Webtoon live have permissions for almost all of their translations