This module is redundant: it tries to solve problems that are already solved by MIME::Base64, but using this module over MIME::Base64 has no advantages yet does have the disadvantages of the encoded format being its own rather than a standard one, so there is no chance of interoperability with anything other than another script using this module, and it would be unfamiliar and confusing to anybody already used to achieving this in standard ways.
Further, everybody already has the MIME::Base64 module (comes as standard with Perl) whereas this one would need installing for use. It also demands Perl 5.8.1 to run (though seems to run with earlier versions if that line is removed).
Finally the module name is badly capitalized ("Text::Toalpha" should be "Text::ToAlpha", to make it easy to see the word boundaries), though it doesn't seem a particularly descriptive name anyway.
The documentation does not explain at all what this module is for. It even warns "The permutation of characters to letters is not very well permutated," whatever that means.
The source code makes no sense at all as to what it's doing. It *seems* to be converting arbitrary characters to letter sequences and back, but the code doesn't look right. It uses a list and hash with some ord/chr conversions. (Why not use pack/unpack?)
Does anything use this code format?
Also, the default h2xs README is there. Not helpful.