Certainly it's worth it to learn perl5. It's not going anywhere. If Perl6 were to be released tomorrow, it would still be years before it had enough penetration to affect most perl programmers. In the mean time, Perl5 is alive and well and will continue to be supported.

Besides, Perl6 doesn't even exist yet. An alpha compiler for Perl6 will maybe exist by the end of 2005.

If you'd like to know what's new and different in Perl6, see http://dev.perl.org/perl6. Read the Apocalypses, Synopses and Exegeses.