Data products from many microwave science instruments are available directly on-line, usually free of charge. You can search and order relevant data at the following data centers:
The Goddard Earth Science Data and Information Service Center provides data for many of NASA's EOS missions. Data can be searched and ordered through their MIRADOR system.
The NOAA Comprehensive Large Array-Data Stewardship System allows users to search an order through many operational data sets. The CLASS search system lets users tune their search options to find the data they are looking for.
The Global Hydrology Resource Center is sponsored by NASA and, among other things, is a repository for the data from many of NASA's flight campaigns. The HyDRO system allows users to search for data.
The JPL Tropical Cyclone Information System was developed to offer data and plots related to hurricanes. This data portal contains historical data from many microwave science instruments.