I've worked with data from excel, preparing the data and converting it to csv using excel first then exporting it to database; it's the easiest way though. LOL :D But never had a chance to work with unicode. Maybe you should try it first, then if you had a problem with regards to the consistency of data, create a program to automate it for you. :)
Anyhow, I would like to know if you really intend to put this thread on PHP, and will be working with PHP. Or should this be on the Databases section.