In my Sharepoint 2001 Document Library to Windows 2003 Sharepoint Services migration app I've found I need to do root out appearances of %20, %25, %27, and %69's from the WebDAV XML output file before porting the files to their new WinSS Document Library home. (Okay, no %69's. I just like to reference the number whenever I can as an, ummm, personal trademark of sorts.)
Hopefully your travels won't find you in the same space-time continuum where unicode translation is required, but if you're trapped in a Yesterday's Enterprise time line and need a good Unicode reference, check out this PDF by the Unicode Society. (Okay, there's no Unicode Society, but there should be.)