You might find the following web-based resources helpful:

  Perl/Tk Tutorial at www.perl.com
  several scripts and articles at www.PerlTK.org,
  A tutorial from Suite101.com in 1, 2, 3 parts
  the Perl/TK FAQ,
  this tutorial which is part of this larger repository of Perl/TK stuff.

And don't ignore the huge collection (over 90 separate files) of other docs on various pieces of the TK collection of tools and widgets -- all included in the installation.