Вы имеете в виду оповещение без обновления страницы? AJAX может сделать это за вас, следующие шаги:
1) Create a php script that fetches the new bugs
2) Add a javascript function that gets the data off the PHP file using getAJAX/getJSON
3) If there is any new data: create an alert or perhaps make a nice looking CSS popup in one corner (or middle) of the screen
Помните, что:
1) You should send some kind of unique identification of a user along with the request to the PHP file, this way you can 'track' which user should have been notified about a bug already.
2) You choose a good interval (e.g. would u use 5 seconds, 2 seconds, 1 seconde, even less?)