Hi Don -
If you're working with a file geodatabase, the text field width can be 2,147,483,647 characters - http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/File_geodatabase_size_and_name_limits/...
If you're working with SDE geodatabases, it depends upon the type of RDBMS you're using - http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Data_types_in_the_DBMS/003n0000001n000...
Good luck!
Robert LeClair
Esri-Denver