This page will let you convert a large number of locations in various coordinate systems (such as latitude/longitude) between coordinate systems. Paste them into the input box (latitude/longitude should be separated by either tabs or commas followed by new lines) and hit the 'Convert' button. The box below should contain the converted coordinates. Copy the output into a CSV file for easier manipulation.
Due to a massive increase in Google Maps costs, geocoding is no longer supported. Sorry.