29. A computer-readable storage medium comprising computer-executable instructions executable in a computer system, the instructions including one or more instructions for: receiving a textual input description, the input description including text to be displayed and a first set of textual cross-references associated with segments of the text to be displayed, each textual cross-reference including one or more textual identifiers for the associated segment of the text to be displayed; receiving a textual output description, the output description including text to be displayed and a second set of textual cross-references associated with segments of the text to be displayed, each textual cross-reference including one or more textual identifiers for the associated segment of the text to be displayed; identifying a first cross-reference in the first set of cross-references associated with a segment of the text to be displayed in the input description; searching the second set of cross-references in the output description to identify a second cross-reference that matches the first cross-reference, the second cross-reference matching the first cross-reference when at least one identifier in the second cross-reference matches at least one identifier in the first cross-reference, the second cross-reference being associated with a segment of the text to be displayed in the output description that corresponds to the segment of the text to be displayed in the input description; and displaying the segment of the text to be displayed in the input description on one side of a display and the segment of the text to be displayed in the output description on the other side of the display.
29. A computer-readable storage medium comprising computer-executable instructions executable in a computer system, the instructions including one or more instructions for: receiving a textual input description, the input description including text to be displayed and a first set of textual cross-references associated with segments of the text to be displayed, each textual cross-reference including one or more textual identifiers for the associated segment of the text to be displayed; receiving a textual output description, the output description including text to be displayed and a second set of textual cross-references associated with segments of the text to be displayed, each textual cross-reference including one or more textual identifiers for the associated segment of the text to be displayed; identifying a first cross-reference in the first set of cross-references associated with a segment of the text to be displayed in the input description; searching the second set of cross-references in the output description to identify a second cross-reference that matches the first cross-reference, the second cross-reference matching the first cross-reference when at least one identifier in the second cross-reference matches at least one identifier in the first cross-reference, the second cross-reference being associated with a segment of the text to be displayed in the output description that corresponds to the segment of the text to be displayed in the input description; and displaying the segment of the text to be displayed in the input description on one side of a display and the segment of the text to be displayed in the output description on the other side of the display. 32. The medium of claim 29 , wherein the first cross-reference and the second cross-reference are coded in the Extensible Markup Language (XML) programming language.