The inclusion of the em-dash on iPhone OS 3.0 was a great inclusion for the typography-minded people; otherwise, we’d have to use hyphens, which are a lame substitution for it. Apple included it, but the conspicuously, the en-dash (shorter version) was missing:
The iPhone can render the en dash correctly, but it is impossible to type it on the keyboard. There may be a way to type it from one of the many international keyboards on the iPhone, but if so I haven’t found it yet. There is one workaround with the new copy and paste function of 3.0: if you are desperate to use an en dash, you can copy it from someplace else and paste it where you want it such as in an e-mail. For example, you could copy the en dash above from this web page, and I am happy to provide this service free of charge.