There are many resources available that you can read and that you will assist in the migration from a old Delphi version to Delphi 2009/2010 (Unicode).
- Unicode Migration Statistics Tool (This utility will hopefully assist you in collecting useful statistics on how hard (or not) it would be to migrate your older applications to Unicode.)
- Delphi 2009 and Unicode
- Delphi 2009 strings explained by example
- Upgrading a major project to Delphi 2009
- Delphi and Unicode
- Dr. Bob Delphi 2009 Unicode
- Delphi 2009 – Unicode in Type Libraries
- On Strings and Unicode in Delphi 2009
- Delphi in a Unicode World Part I: What is Unicode, Why do you need it, and How do you work with it in Delphi?
- Delphi in a Unicode World Part II: New RTL Features and Classes to Support Unicode
- Delphi in a Unicode World Part III: Unicodifying Your Code
- CodeRage 4 : Using Unicode and Other Encodings in your Programs
The Road to Delphi 