I'd say multi-core programming isn't just the future, it's the present. It's been at least a couple years since anything I wrote ran on a machine with just one core. Usually the kind of parallelism I need is easy to get - Apache/mod_perl runs multiple copies of my code and on the backend MySQL runs multiple threads to service them. For slightly harder problems requiring some coordination between processes I use Parallel::ForkManager and pipes with IO::Select.

I'm very sweet on Erlang, but whether it's right for you is something only you can judge. You might get to market faster by leaning on the built-in parallel features or you might get bogged down in the learning curve of a new environment. I think a lot depends on just how much parallelism you need to exploit - if we're talking about dual and quad core machines then some fork()ing Perl code is probably good enough. If you're deploying on a cluster of several hundred 32-core machines, well, you might need more management ifrastructure and going with a pre-built system may be a better idea than rolling your own.

-sam