I used glibmm (
http://www.gtkmm.org/documentation.shtml) on a project to collect user information (how much they used
computers etc.) to a database. Since the machines were different kinds of Unix servers and
the database was Microsofts SQL Server, I used glibmm's usting, which converts different
encodings to UTF-8. The catch is, glibmm is for C++ and you did not told what language
you are going to use.