You can use iconv command under Unix (also available on Windows as libiconv).
After saving as CSV under Excel in the command line put:
iconv -f cp1250 -t utf-8 file-encoded-cp1250.csv > file-encoded-utf8.csv
(remember to replace cp1250 with your encoding).
Works fast and great for big files like post codes database, which cannot be imported to GoogleDocs (400.000 cells limit).
