Working on improving everything OSM focused on Brooklyn. Also interested in mapping foot and bike paths around the city and elsewhere that are not documented on standard maps. I may run a mapping party from time to time and I would like to meet other NYC mappers.
Here are some links to get you up and running.
First, Install JOSM so you can edit the map
Learn how to use JOSM here
Introduction to OSM
There are a lot of links to click to navigate through this beginners guide, but it is a pretty good introdution covering collecting data with a GPS through editing.
Using GPS Babel
GPSBabel will translate from one GPS device file type to the universal GPX file format needed by JOSM or the KML format needed by Google Earth. You can download a MAC version and use the easy user Interface to choose your device file type from a list of files types. Here is a an example: