There have been several updates to different versions of OggPlay the software that allows you to play .ogg (and .mp3 on some phones) files. The most recent versions are available from this page. Recent updates include better support for the Sendo X (in the Series 60 Non MMF version) and support for WinAmp playlists across all version. The MMF version (for Series 60 2.0 phones) ties into the multimedia framework of the phone and can play back MP3, MP4 and AAC files as a result. More information is available on OggPlay here.