encoding

I need some advice about what encoding type to use.  I have a database
used as a back end for a web site that provides language study flashcards
(among other things).  Mostly we are talking about english to some other
western language.  English/Spanish, English/German etc.  For some reason
I thought that SQL_ASCII wasn't going to handle russian text like
"Государство
Российское",
much less spanish/french accents but I just tested it and it went in
fine.  So... what are the limitations of SQL_ASCII?  No CKJ?  I want this
to be as flexible as possible but when I tried to convert the the
database from SQL_ASCII to UNICODE or MULE_INTERNAL it blew up.  I tried
different options on pg_dump but I couldn't get it to convert the data in
one of the tables (the table contains raw email messages).

culley