For the first part, glob is simpler:

my @perlfiles = glob "*.pl";
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If you're talking about HTML output, this will work:

use CGI;
# ... don't forget to output header, startform
print CGI::radio_group(-name => 'perlfiles', -values => \@perlfiles);
# ... submit button, endform
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But as thousands of words worth of perlmonks entries will tell you, CGI.pm is a lousy solution for creating HTML for any but the most trivial applications. A template system is much better. See HTML::Template or do a SuperSearch for lots more options.