This keeps coming back thanks to spammers, but anyway...

How do I get the extra characters used in Turkish and Hungarian when using an iPhone? İ, ı, Ğ, ğ, Ő, ő, Ű, ű and a few others.

The usual accented-character trick of holding down the iPhone on-screen keyboard widget for the base letter and selecting from a small menu doesn't work - the little menu doesn't have those characters.

This is just for typing occasional words (musical terms, names) when the surrounding text is in English - I don't want to turn the whole interface into a foreign language.