By default, every e-mail you send from your iPhone includes the same signature: "Sent from my iPhone."
Nice as it is to crow about your hip, trendy choice of communicator, you might want to consider something different. For example, maybe you don't want the boss to know you're out and about instead of slaving away at your desk. Or maybe you feel the sig needs a dose of your sparkling wit.
Whatever the case, it's easy to change your e-mail signature. Tap the Settings icon, then tap Mail, Contacts, Calendars. Scroll down until you find Signature and give that a tap.
Now just edit the text. You can delete the signature altogether or create something new from scratch. Alas, you can't add HTML or graphics; you're limited to little more than plain text.
So, let's hear your ideas for clever e-mail signatures. (Surely you can do better than the one pictured above.) Or is it enough to tell the world, "Nyah, nyah, I have an iPhone"?