charset correction (utf-8) for uploaded (txt/html) documents

[testbird]

If you find a way to do this in ruby, I would be glad to add some
zafu/rubyless methods to support the transformation, probably by
having some form field with the encoding and Zena would tranform to
utf-8 before saving to the database...

For ruby 1.8 people are pointing to the iconv gem:
http://stackoverflow.com/questions/3663513/simple-conversion-of-string-to-utf-8-in-ruby-1-8
http://stackoverflow.com/questions/12947910/force-strings-to-utf-8-from-any-encoding
http://stackoverflow.com/questions/951891/how-can-i-convert-a-string-from-windows-1252-to-utf-8-in-ruby

Ruby 1.9 seems to come with a build-in encode method.