File Formats

ESRI Shapefile Technical Description
http://www.esri.com/library/whitepapers/mo_lit.html

Java Shapefile Reader v1.0Beta1
http://www.geog.leeds.ac.uk/pgrads/j.macgill/java/JavaShapefile.html

Global Geomatics - Geospatial Data Format Reference
http://www.globalgeo.com/doc/ref_guide/adapters/default.asp

Every File Format in the World
http://whatis.techtarget.com/Flat_Files/WhatIs_File_Format_A/0,281899,,00.html

Graphics/fileformats FAQ
http://www.landfield.com/faqs/graphics/fileformats-faq/

Graphics File Formats Page
http://www.dcs.ed.ac.uk/home/mxr/gfx/

Wotsit's Format - Programmers Resource
http://www.wotsit.org/

File Format Converters

ESRI ArcView Shapefile to AutoCAD DXF/DWG Converter
http://www.sscnet.ucla.edu/geog/gessler/167-2001/file-formats.htm

Miscellaneous

Shape Projector AVX allows users to project ESRI shape files from any coordinate system to another, including datum and unit conversions.
http://www.rockware.com/catalog/pages/shapeprojectoravx.html