What Fletch siad about readdir. This is how I typically handle it however:

chdir $dirtoget;                  # Notice!
opendir(IMD, '.') || die("Cannot open directory");
@thefiles = readdir(IMD);
closedir(IMD);

foreach $f (@thefiles)
{
   if (-d $f)
   {
       print "$f<br>\n";
   }
}
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Sometimes chdir isn't the best answer, but it often is.