Whitespace TextMate Bundle
This is a simple TextMate bundle that strips out trailing whitespace and replaces tabs with spaces whenever a file is saved. Read more about it on the Viget Labs developer blog.
Installation:
mkdir -p ~/Library/Application\ Support/TextMate/Bundles
cd ~/Library/Application\ Support/TextMate/Bundles
git clone git://github.com/vigetlabs/whitespace-tmbundle.git Whitespace.tmbundle
osascript -e 'tell app "TextMate" to reload bundles'
Copyright (c) 2009 Viget Labs, released under the MIT license