webdav access to ~/public_html

I'm a newb when it comes to any apache configuration that requires
more than uncommenting some lines in the default config. Sorry.

I'm looking for a recipe to allow our users to maintain their Sunbeam/
Lightning calendar files under their ~/public_html, ie ~/public_html/
ical/user.ics.

Here's some crap I came up with that doesn't work, but it might help
explain what I want:

#
# Control access to UserDir directories. The following is an example
# for a site where these directories are restricted to read-only.
#
#
# AllowOverride FileInfo AuthConfig Limit
# Options MultiViews Indexes SymLinksIfOwnerMatch IncludesNoExec
#
# Order allow,deny
# Allow from all
#
#
# Order deny,allow
# Allow from all
#
#

/home/*/public_html/ical>
Dav On
AuthType Basic
AuthName DAV
PerlAuthenHandler Apache::AuthenNIS
PerlSetVar AllowAlternateAuth no
require valid-user