The latest version of the WordPress OpenStreetMap plugin focuses on GPX tracks and bugfixing:
* NEW: extended rights to upload GPX files in the WP Mediathek
* NEW: CSS file to adapt to local needs
* FIX: WP-Theme zBench fix
* FIX: HTML tag if post is geotagged
* FIX: z-index at shortcode generator
Sites about this plugin:
* Download: http://wordpress.org/extend/plugins/osm/
* Plugin-site: http://www.fotomobil.at/wp-osm-plugin
* Plugin-forum: http://www.fotomobil.at/wp-osm-plugin-forum
* Wiki-site: http://wiki.openstreetmap.org/wiki/Wp-osm-plugin
* Author-Blog: http://www.HanBlog.net
Find an article on this plugin version with samples about GPX tracks in OpenStreetMap: