There were only a small handful of ones actually related to anime, but here's some free Japanese-language inductions.
I think NicoNicoDouga still requires registration, but you should be able to do it in English now (damn whippersnappers, uphill in the snow, etc.).
http://www.nicovideo.jp/watch/sm10747103http://www.nicovideo.jp/watch/sm14500065Listenable Pharmacy has a bunch on their page, mostly voiced by Phan Masaki:
http://www.nct9.ne.jp/d3online/すくりぷてっどこねくしょん has a nice variety:
http://107baknyuata.blog110.fc2.com/blog-date-200712.htmlHypnoVoiceFan keeps a list of more or less every single free Japanese hypnosis audio, by creator. It's a bit hard to use; the links go to the creators' webpages and you may have dig around from there.
http://www.saiminfan.net/?p=453Or the easier-to-use list of every induction from 2012:
http://www.saiminfan.net/?p=1100Download passwords are usually located below the corresponding link; just ask if you need any help downloading anything.