Official site is
http://pear.php.net/package/HTTP_WebDAV_Client 
.
I created this package for our own purpose, but anyone can use it.
Major differences compared to the original HTTP_WebDAV_Client, are:
- Implementation of local buffer. You can set buffer_size context option to reduce httpd server-client communication overhead. *1
- support of user_agent stream context option.
- support of content_type stream context option.
*1) Default value of the chunk size is 8192 (defined in PHP stream system), so if you want to upload 3MB file, you have to process almost 400 http requests.
This problem is reported as
http://pear.php.net/bugs/bug.php?id=13245