It seems that some series are available online for free. Stretch being the most obvious one, but the latest chapter of Kase-san too. I know there are at least a few people here who like to read in Japanese, so maybe we should put up a list of places with free yuri manga, or yuri webcomics?

Stretch is on やわスピ which is an online magazine so there are other comics there too (I haven't read any of the others except Kumacchau so I don't know if there is any other yuri):
http://yawaspi.com

Kase-san is on yahoo books:
http://bookstore.yahoo.co.jp
There are lots of free manga chapters in the "free corner" but finding yuri stuff may be hard. I only found Kase because it was linked from this forum (if you search 加瀬さん it also comes up).

If anyone else knows some good sites it would be great to know.