There exist a number of information systems planning(ISP) methodologies. As the level of market competition gets intensified, firms are more likely to engage in organizational transformations such as BPR and CPI(continuous process improvement). Because this new requirement should be incorporated into ISP methodology, the number of ISP methodologies available will be continually increasing. However, we could not find a framework for understanding and classifying these divergent methodologies. So, we here present a framework for classifying ISP methodology classes. With this framework, we categorize different classes of ISP methodologies and identify their limitations in terms of missing elements and links. And we move on to present new technical innovations and other methodological advances that, if properly integrated with ISP methodologies, would help us derive an IT infrastructure plan more effectively. Furthermore, in search of software tools or aids supporting the application of ISP methodologies, we identify requirements of ISP-supporting software tools and evaluate functions of existing software tools, then suggesting a future direction to that end,