Mippin.com – Does a good job of showing mobile webpages quickly but returns mobile pages instead of the desktop versions (Hard to explain without seeing it 🙂 It actually does a great job of displaying Blogs compared to news sites such as cnn.com.
Mowser.com – Personally I think this is better than mippin and does not have a cluttered homepage so it is easier to use. My complaint is that it makes text very large.
Skweezer.com – This is actually used by Viigo to provide mobile optimized versions of the full article in an RSS feed. it works quite well but does not always look ideal since it strips out much more than Mowser and Mippin.