I setup subversion by integrating with apache2.2.8. I also used the windows active directory for authentication. I did the following steps on the windows machine.
1.Downloaded and installed subversion( version 1.5).
2.Downloaded and installed apache2.2.8
3.Copy all dll’s and modules from subversion/bin directory to the apache2.2 /modules directory
4.Load the following modules by editing apache/conf/httpd.conf
LoadModule dav_module modules/mod_dav.so
LoadModule dav_svn_module modules/mod_dav_svn.so
LoadModule ldap_module modules/mod_ldap.so
LoadModule authnz_ldap_module modules/mod_authnz_ldap.so (note: authnz and not authz as earlier releases of apache)
5.Restart apache server.(If complains about loading modules check these following platform specific notes else conveniently ignore the following)

6.If all is well create svn repository
svnadmin create C:\svn\repositories
7.Edit apache/conf/httpd.conf to add the repository location information and your windows active directory details.

<pre name="code" class="brush:xml"><Location /svn>
DAV svn
SVNParentPath C:/svn/repositories
# Disables Path Checking
SVNPathAuthz off
# Display available Repos
SVNListParentPath on
Allow from all
SetHandler ldap-status

AuthType Basic
AuthBasicProvider ldap
AuthzLDAPAuthoritative off
AuthName “some meaningful name”

AuthLDAPBindDN “usersgroup@companyname.com”
AuthLDAPBindPassword
AuthLDAPURL “ldap://companyname.com:3268/DC=companyname,DC=com? sAMAccountName? sub?(objectClass=*)”
require valid-user
</Location>
</pre>
8.Save the http.conf and restart the apache.
9.Access the subversion using the url http://yourmachinename/svn
10.The browser will prompt for login. Login using your credentials and access the subversion.

If interested in active directory and new spring security 2.0.4 read
Spring Security with AD

Notes: If your login failed check your apache error log file.
Most common errors you may see are
1.auth_ldap authenticate: user butters authentication failed; URI /svn/ [LDAP: ldap_simple_bind_s() failed][Invalid Credentials]
to resolve the above try to talk with your windows active directory administrator and find out about the port info like 389 or 3286 should be used etc…
2.[ldap_search_ext_s() for user failed][Operations Error]
this error is good sign your able to connect to win AD but not able to find the user.
since win AD does not allow anonymous binding make sure you have the correct AuthLDAPBindDN
AuthLDAPBindPassword info.