ALL 96 and later cars and light trucks MANUFACTURED for sale in US market are OBDII compliant/equipped. Newer connection standard starting to come through on some vehicles is OBDII CAN which will be mandated by 2008. See
http://www.gendan.co.uk/articles.php?article=9
OBDII General info
http://www.obdii.com/
http://www.flatratetech.com/pub34.htm
List of generic OBDII codes
http://www.autotap.com/generic_trouble_codes.html
http://www.obdii.com/codes.html
Code lookup (page is slow and doesn't always work)
http://www.autotap.com/codes.asp