The fourth "OGSI and Microsoft .NET" course, provided as part of a collaboration between NeSC, EPCC and Microsoft Research Ltd, was held on February 2425th at the e-Science Institute in Edinburgh. Fourteen delegates attended the course from a range oforganisations across the UK involved or interested in eScience, Microsoft and the Grid. These organisations included Forest Research, Kings College, London, Liverpool John Moores University and the Universities of Portsmouth and Edinburgh. The goals of the course were to provide attendees with information on both the Open Grid Services Infrastructure and Microsoft .NET and to demonstrate the applicability of Microsoft .NET to the development and hosting of Grid services. An implementation of OGSI on .NET - MS.NETGrid-OGSI 1.2 - was used as a focus for course practicals. The attendees viewed the course very positively and worth their while attending, stating that it provided a clear introduction to both OGSI and Microsoft .NET. Grid service development practicals – providing hands-on use of Microsoft .NET tools and MS.NETGrid-OGSI – were viewed as particularly useful and interesting.