ora_mail is a tool for those of us who do not want to enable JServer for one reason or another. It is implemented as an external procedure that reads message data from CLOBS and passes it to and external program, such as qmail-inject or sendmail. There is also PL/SQL package that wraps arround this procedure to ease message creation.
CPPSERV is a Web application server / servlet container that provides a Servlet-like API to C++. It also contains CSP (C++ Server Pages) functionality, similar to pre-compiled JSP. It consists of stand-alone application server and Web server front-ends. Modules for Apache and lighttpd are available.
Use CPPSERV instead
mod_plsql is fine idea, and will work for simple applications, but for anything even mildly complex, one needs real application server. My personal recommendation is CPPSERV: it is an application server that provides very Java Servlet-like API to C++ programmers, and also contains CSP (C++ Server Pages) parser.