This list includes databases, food regulation websites and related pdf documents from various national, regional and international authorities:

ASEAN
Harmonization of MRLs of Pesticides for Vegetables

Australia
MRLs in food and animal feedstuff
Codex in Australia

Canada
MRLs for Pesticides
Codex in Canada

EU
Food Safety
MRLs by substance
European status

FAO/WHO Codex Alimentarius Commission (CODEX)
FAO/WHO Food Standards
Pesticide Residues in Food, MRL database

Indonesia
Pesticides Committee

Japan
Positive List System for Agricultural Chemical Residues in Foods

Netherlands
RIKILT - Institute of Food Safety

New Zealand
Codex

Spain
MRLs in legislation, database

Taiwan
Pesticide residue limits in food, 15 March 2006

UK
UK, EU & CODEX MRL Database

USA
Pesticides: Health and Safety
International MRL Database for US Specialty Crops