Instead of an app, today we have a tip for the iPhone and iPad that you may not be aware of.
In their recent release of iOS5, Apple added some cool new features to the iPhone/iPad's mail application. These features are pretty hidden though, so here's how to use them.
When you are composing an email, select a word (or a phrase of words) by tapping and holding the word and then choosing "Select":
Then tap on the right arrow in the floating pop-up menu:
The hit the B/i/U button:
And voilà, you can now add bold, italics, and underline the text you have selected in your mail:
As you can see, this also gives you the ability to look up a word (this is also available in other native iPhone apps, like the Notes app) and can increase/decrease the quote level.
Here's a bonus tip: if you go to Settings > General > Keyboard you can now also setup your own shortcuts. Shortcuts are text macros that you can use across all applications in your iOS device (like Mail, SMS, Notes, or any other application that uses the keyboard).
You setup a short phrase, like "brb", "5min", "wcl", and then determine what full text you want those to expand into ("be right back", "give me 5 minutes", "will call later", etc...).
Pretty useful stuff.