Use the magic module for better (content based) MIME type guessing if
mimetypes does not return a type.

diff -up eyeD3-0.6.17/README~ eyeD3-0.6.17/README
--- eyeD3-0.6.17/README~	2009-02-02 05:54:52.000000000 +0200
+++ eyeD3-0.6.17/README	2010-05-25 19:43:21.000000000 +0300
@@ -20,6 +20,7 @@ See the NEWS (NEWS) and/or ChangeLog (Ch
 Requirements
 ============
  - Python (http://www.python.org/) >= 2.3
+ - python-magic (http://www.darwinsys.com/file/, optional)
 
 Installation
 ============
diff -up eyeD3-0.6.17/src/eyeD3/frames.py~ eyeD3-0.6.17/src/eyeD3/frames.py
--- eyeD3-0.6.17/src/eyeD3/frames.py~	2009-02-02 05:54:52.000000000 +0200
+++ eyeD3-0.6.17/src/eyeD3/frames.py	2010-05-25 19:39:13.000000000 +0300
@@ -18,7 +18,7 @@
 #  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 #
 ################################################################################
-import sys, os, os.path, re, zlib, StringIO, time, mimetypes;
+import sys, os, os.path, re, zlib, StringIO, time;
 from StringIO import StringIO;
 from utils import *;
 from binfuncs import *;
@@ -1274,12 +1274,12 @@ class ImageFrame(Frame):
        # Load img
        fp = file(imgFile, "rb");
        imgData = fp.read();
-       mt = mimetypes.guess_type(imgFile);
-       if not mt[0]:
+       mt = guess_mime_type(imgFile);
+       if not mt:
            raise FrameException("Unable to guess mime-type for %s" % (imgFile));
 
        frameData = DEFAULT_ENCODING;
-       frameData += mt[0] + "\x00";
+       frameData += mt + "\x00";
        frameData += bin2bytes(dec2bin(type, 8));
        frameData += desc.encode(id3EncodingToString(encoding)) + "\x00";
        frameData += imgData;
@@ -1528,11 +1528,10 @@ class ObjectFrame(Frame):
        if mime:
            print("Using specified mime type %s" % mime);
        else:
-           mt = mimetypes.guess_type(objFile);
-           if not mt[0]:
+           mime = guess_mime_type(objFile);
+           if not mime:
                raise FrameException("Unable to guess mime-type for %s" %
                                     objFile);
-           mime = mt[0];
            print("Guessing mime type %s" % mime);
 
        frameData = DEFAULT_ENCODING;
diff -up eyeD3-0.6.17/src/eyeD3/tag.py~ eyeD3-0.6.17/src/eyeD3/tag.py
--- eyeD3-0.6.17/src/eyeD3/tag.py~	2009-02-02 05:54:52.000000000 +0200
+++ eyeD3-0.6.17/src/eyeD3/tag.py	2010-05-25 19:39:54.000000000 +0300
@@ -17,7 +17,6 @@
 #
 ################################################################################
 import re, os, string, stat, shutil, tempfile, binascii;
-import mimetypes;
 from stat import *;
 from eyeD3 import *;
 import eyeD3.utils;
@@ -1700,7 +1699,7 @@ class Mp3AudioFile(TagFile):
 
 ################################################################################
 def isMp3File(fileName):
-    (type, enc) = mimetypes.guess_type(fileName);
+    type = eyeD3.utils.guess_mime_type(fileName);
     return type == "audio/mpeg";
 
 ################################################################################
diff -up eyeD3-0.6.17/src/eyeD3/utils.py~ eyeD3-0.6.17/src/eyeD3/utils.py
--- eyeD3-0.6.17/src/eyeD3/utils.py~	2009-02-02 05:54:52.000000000 +0200
+++ eyeD3-0.6.17/src/eyeD3/utils.py	2010-05-25 19:47:58.000000000 +0300
@@ -180,3 +180,23 @@ def format_time_delta(td):
     if days:
         tstr = "%d days %s" % (days, tstr)
     return tstr
+
+################################################################################
+# MIME type guessing
+
+import mimetypes
+try:
+    import magic
+    _magic = magic.open(magic.MAGIC_SYMLINK | magic.MAGIC_MIME)
+    _magic.load()
+except:
+    _magic = None
+
+def guess_mime_type(filename):
+    mime = mimetypes.guess_type(filename)[0]
+    if not mime and _magic and os.path.isfile(filename):
+        mime = _magic.file(filename)
+        if mime:
+            mime = mime.split(";")[0]
+    return mime
+