"20 users online" style user tracking is a favourite of ASP websites. This class allows you to do the same thing easily with PHP. The OnlineUsers class uses a leightweight MySQL table to track the users, logging them to a table. Details of who is online and how many users is then easily retrieved.

Who's Connected is a set of two small PHP scripts that use MySQL to display the number of users who have viewed a page within the last minute (can be modified). First script will add the connection to a table in MySQL. The second script will display the number of users.

zerofil onlinestats is a php script which allows you to easily include a total visits counter and a "X user-online" features to websites. It uses three flat text files to store data: log.txt which logs date, IP, name of page; total.txt which counts the number of total visits and online.txt that stores info about online users. You can easily add features, place the counter anywhere you want to. Comes with an english instruction.

user-online is a php- script which allows webmasters to include the "xx user-online" features to their websites. It counts the users who are online since a defined time and shows the count of users in a small table, which can be placed everywhere the website. the content of the table is sorted by the count of users in particular directory.