Dynaloader is a CPAN module, so a Google search for "cpan Dynaloader" will have the Dynaloader POD documentation as the first result. You could also get that with the command perldoc Dynaloader on a system with Perl (and Dynaloader) installed.
You can look at the source code with the "Source" link near the top left of the CPAN web page. If you are on a Unix-like system, locate -i DynaLoader.pm should find a copy of the source code on your system.
If you have a more specific question after looking through the source code feel free to ask.