The objective of this research is to seek the exact nature of how an organization should apply a serviceoriented design to systems that were previously standalone heterogeneous applications. For this objective, three applications are developed and integrated by using a service-oriented architecture: a biometric attendance system, a surveillance system, and a point of sale system. Each application is classified by a combination of two properties: input or output heavy application, local or remote running application. Based upon the combination, two types of service-oriented integration approach, fully or partially web serviced integration, are suggested according to the extent of the usage of web services. Based upon the experiences gained from developing the three applications, the guidelines for adopting web services are proposed when an organization is integrating applications.