A few years ago I came across the site Copy Paste Character, which allows you to simply click and copy symbols from a library. It is an incredible resource for me as a designer because it allows me to access symbols that normally would take some time to figure out the keyboard shortcuts.
Well now this resource is available for your iPhone for $0.99. It offers the same simple touch to copy and paste feature as the original website. So now you can add fun symbols to your status updates, text messages, or emails.
If $0.99 is out of your budget, there is a free version of a similar application here.