I missed having an icon for Python files in TextMate, so I made one with a Python Logo on it:

You can add it to your TextMate by downloading this file and putting it unter Contents/Resources/File Icons/ within your TextMate.app folder (to open that folder in the Finder, go to Applications, right-click TextMate and choose “Show Package Contents”).
Then open the file Bindings.plist (located in the same folder where you put the .tiff) in your favorite text editor and add this anywhere directly after a “</array>”:

<key>PBX-python-Icon</key>
<array>
<string>py</string>
</array>

That’s it! Restart TextMate and you’re done.

If you’re looking for better folder icons, there’s a blog post for that, too.

Update: The icon file is gone from the above URL, but there is now a zip file by Aaron Jackson on the Macromates Wiki.