Recently, service providers are interested in developing geolocation-based servies of users such as weather dan traffic information using mobile positioning technology. GPS is widely used for determining user's position in an outdoor environment. but GPS lacks reliable performance in an indoor invironment. because of these reasons, we offer a positioning system application that utilizes wireless LAN which is commonly found in most laptops today. the positioning system uses location fingerprinting method which consists of two phases; training and positioning. the objective of training phase is to build a fingerprint database, which is a received signal strength (RSS) data from each installed access point. in order to minimize time needed to do site survey, weighted distance inverse interpolation is used. in the positioning phase, user sends RSS data to server and the position is determined based on the fingerprint database. the result of the expriment shows hat the positioing system reliability depends on the fingerprint database.RSS data, which is the mai fingerprint data is very sensitive to environment condition. accuracy of the positioning can be improved by adding more access points and determining optimal number of reference points. this application can be developed further so that it can cover wider area.