JMp3Tag - Java application to edit tags in MP3 files. Many phones do not have an in-built editor to edit these tags (even mine doesn't) and hence I wrote this application.
Tags are chunks of data stored within the audio file to help identify the content. Commonly used tags are - Title, Album, Artist, Year etc. Many audio players display theese tags when a track containing tags is played and allow to group the tracks based on these tags. These tags are stored using a format named as ID3 (version 2.3.0). You can find more about the tagging format at http://www.id3.org/id3v2.3.0 here
JMp3Tag runs on Java phones (MIDP 2.0 and above). The phone should also support JSR-75 API. This API is required to read/edit the filesystem.