If you use foobar as audioplayer, you can try foo_openwith, a plug-in that let's you launch external applications, like the "Tools" in Mp3tag.
You can use "/fn:%_path%" as Main parameter to start mp3tag via context menu from foobar to quickly tag your files.
Another plug-in foo_run which does the same can be found here
foo_run also has been ported to foobar2000 0.9 by Florian 