Twittervision for the iPhone put out a great update over the weekend that does something even the desktop version cannot do. You can now double-tap any foreign-language tweet, and it will convert it into your native language.
Why is this important? If you ever used the previous iteration of the application, you know that it simply jumps around the globe, showing you random Twitter status updates. Many cannot be read unless you're fluent in that language, making it cute but fairly useless for most folks.
The translation takes about 10 seconds to work its magic, and you've got to be quick to touch, considering that the application hovers on a tweet only for half that amount of time. You can also single-tap any tweet with a link, and it will open it up in a minibrowser that includes a small plus button to bookmark the page for later reading.