Today I have just looked up this blog’s stats. Evidently the most read post is my complaint about the difficulty of getting free WebDAV service. Well, from the comments and some research of my own I now can inform you at least there are two free WebDAV services: Mydisk.se and Swissdisk.com.
Mydisk.se offers 2 GB free WebDAV storage, with caveat: if the account is inactive in 3 months, the files will be deleted. Swissdisk.com only offers 50 MB of storage, but doesn’t have activity requirements to retain your data.
Update: MyDrive.ch also offers free WebDAV service. See also first comment here.