I'm from Brazil and have been interested in the project since late 2007.
I'm mapping São Paulo, my hometown, using a Holux GPSlim240 bluetooth GPS, Nokia N95 8GB (with SportsTracker), Nokia N800 Internet Tablet (with MaemoMapper and OSM2GO) and the Yahoo! imagery. Most of the stuff mapped in São Paulo city was made by myself and a couple other people.
I'm also interested in developing a Java apllication (JME or J2ME) that you could use in your phone with the data from Open Street Map.
My OSM name is diogow