HiFor web based mapping applications we've got a few options which may be of interest to you.You should take a look at the ArcGIS Online capabilities for "cloud" based solutions http://www.esri.com/software/arcgis/arcgisonlineIf you want to develop your own applications (which can consume either your own hosted services or ArcGIS Online services and webmaps), then you need to look at one of the web APIs we offer. We have APIs for FLEX, Java Script and WPF.There are some links below and forums for each of these products. General link : http://www.esri.com/getting-started/...rs/get-started - Flex : http://www.esri.com/getting-started/...t-started/flex - Java Script: http://www.esri.com/getting-started/...ted/javascript There are loads resources available on all of these products. Let me know if this helps. Good luck Mark