mod_perl is an open source project and is very successfully supported by its users and developers community. Most of the questions are answered on the mailing lists.
You can learn mod_perl by yourself through reading its documentation, by attending the technology conferences or inviting a commercial training.
If however you need a commercial level support, the following companies are available for mod_perl contracts and support.
The following ISPs claim to support mod_perl.
If you are looking for a mod_perl job or someone to do the job for you, the jobs page is for you.