Oracle problem with encoding

I have oracle 10g and my db is in AL32UTF8, I had install oci8 from
oracle but when i run a query the greek characters returns with ???. I
tried also with dbi but with no luck. My ruby version is 1.8.7 and my
system ubuntu 10.04. Here is my code:

require 'rubygems'
require 'unicode'
require 'iconv'
require 'oci8'
require 'jcode'

conn = OCI8.new('user', 'password', 'host/db')
conn.exec('select * from tablet ') do |r|
puts r

end
conn.logoff

Any suggestions how to change charset enconding?

Thank you

I found the answer, it is:

ENV =[NLS_LANG =AMERICAN.AMERICAN.AL32UTF8]

Thank you

Johndel,
I came across your post since I have the same issue. Could you explain
your answer a bit? Where did you enter that information?

regards,

Rutger