there's not yet a stable release of mod_perl supporting httpd-2.4.x: 2.0.8 will be when it will be released.
work is going on in its httpd24 svn branch: I've just tested the latest revision (modifying pprkut's build script) and seems usable (last time I checked it wasn't).
If you want to try it a testing build is here
http://ponce.cc/slackware/testing/mod_perl/