It seems that the world we be a better place without the pdf file. Using the JailbreakMe method, hackers can now gain control of your iPhone just by viewing an infected pdf file. It works by causing a stackoverflow error with the fonts, thus crippling your iPhone’s security and allowing the hacker to do what he wants.
If you have a jailbroken iPhone, you can prevent this by installing the PDF Loading Warner plugin off of Cydia. It provides a warning before viewing a pdf file, allowing you not to view the pdf (This doesn’t fix the vulnerabilityi though)