GTK2 Text Editor is a simple Unicode text editor that supports many encodings. It works as a nice Notepad replacement, and can also be used as an encoding converter. It supports multi-level undo, right to left text (as in Hebrew), and other Unicode features. It can auto-close an XML/HTML tag. There is no syntax highlighting yet.
OmegaT is a translation memory application intended for professional translators. It does not translate for you (software that does this is called "machine translation"). It features fuzzy matching, match propagation, simultaneous processing of multiple-file projects, simultaneous use of multiple translation memories, and external glossaries. Document file formats include plain text, HTML, and OpenOffice.org/StarOffice. It has Unicode (UTF-8) support (can be used with non-Latin alphabets). It is compatible with other translation memory applications (TMX Level 1).