There are some basic operations, that any Internet Service Provider (ISP) must do, such as adding, removing users, disabling and enabling users, changing user passwords etc. Beside these basic operations, all ISPs must design a accounting system to bill the users. Most of the currently available ISP packages run on Windows NT or UNIX systems and in client side a specific client program is developed, which runs only on specific operating system (OS) (say Windows NT). If ISP want to access these ISP operations from an another OS (say from UNIX (with hundreds of its derivatives), OS/2, MacOS etc.), client program must be ported to each of the OS. Although this is possible in theory, in practice it is very difficult and not cost effective.In this thesis to solve this problem, a Web based user accounting system IS proposed. In a Web based system anyone who has a regular Web browser can access the ISP data, manage and view them (ofcourse securely) no-matter where he is in the world which OS he uses. This approach makes ISP accounting easy and cost effective. Additionally making the system in Turkish, increases the useability of the system for the Turkish users.