Many agencies dedicate space on their homepage to the latest news and updates, here are a few samples:
Colombia
El Salvador
Fiji
Finland
France
Iceland
Japan
Korea
Lithuania
Pakistan
Singapore
Slovakia
Taiwan
Ukraine

 
Many competition agencies offer subscriptions to electronic newsletters or email alerts about their activities and news. Here are a few examples:
Portugal
Australia
European Union
Ireland
Poland
Ukraine
United Kingdom
Zambia
Sweden
South Africa