From the files of the Worth Mentioning Again Dept.: If you're jailbreaking your iPhone for whatever reason, be sure to change the root access password once you do. Besides hacker ransom attempts, it's just good security sense.
The Just Another iPhone Blog provides the steps needed, from first jailbreaking to final lock-down, to get a new, custom root password installed. By default, your iPhone's root password is alpine—and everybody with a bit of iPhone savvy knows that. Especially when you open up your phone for tethering access, anyone who knows your iPhone's IP address could potentially jump into the very deep guts of your phone and—well, let's just presume they wouldn't leave you a nice pop-up message.
Hit the link for a quick tutorial and a bit of long-term safety.
How To Change the iPhone's Root Password [Just Another iPhone Blog]