The facilities you describe are already delivered with unix (see man fg and it'll tell you about all the related commands). They can be found under Solaris in /usr/bin. When executing these from Perl (e.g. with the system command) there will be a shell process in between, so you'll have to give fg or bg the specific pid as argument. But you can get the pid when creating the background job, for example, if spawning it using Proc::Simple.

Update: To be more precise about the last point, having used the new and start methods, you can then use the pid method to retrieve its pid.