I realize this tip really applies to using any service (like online banking, facebook, twitter, etc) which offers a way to submit data via SMS text messages, but I found a neat way to use it on the fly with my online banking service. 

Like a lot of businesses, my banking’s online services offer a VERY limited set of transactions that can be completed by simply sending a text message to a prescribed number that is pre-approved via their Web interface.  In other words, your phone MUST be entered in and subscribed to their service by way of their Web site, so only your phone can access your account.

How does this work?

1. I logged into my bank’s online Web site using several secure passwords and tokens.
2. I subscribed to the SMS banking service, providing my phone number, carrier, and other secure details
3. The Web site provided me with their SMS number (usually 5 digits) and a short list of commands like BAL(ance), and TRANS(fer).
4. On my iPhone 4S, I set up a contact for “Bank” which — as the phone number — contained the 5-digit SMS number provided by my bank.

Now, from anywhere I have phone service, I can raise the phone to my ear (activating SIRI) and say “Message Bank BAL“.  SIRI asks me to confirm, and within just a second or two, my bank answers back with my balance via text message (which I immediately delete from my phone).

Is it secure? Sure.  About as secure as the online Web site as long as I don’t keep the messages on my phone.  The commands available also don’t let me do anything destructive like “send money to hackerX” or “make payment to JoeBlow”.  Otherwise, I need to make the clear disclaimer that I’m NOT a security professional, and you should use these tips at your own risk.

Twitter, Facebook, and others

Like the example above, you can subscribe to similar services inside most social networks, add a new contact (like Facebook) to your 4S, and use SIRI to say “Message Facebook blah blah blah” and it’ll post “blah blah blah” to your status message on Facebook, which is all sorts of wicked cool..

While I hate the idea of wasting my limited text messages every month to do this, at least with iMessages, you could theoretically avoid such a charge.

UPDATE: I have to do a little more testing, but with the recent outages in SIRI processing, you might need to disable the option to share your Contacts in the iCloud, making them local to your phone.  Something about the time delay between asking SIRI to send a message and the phone having to look up your contact in the cloud seems to be causing an issue.  You can temporarily disable this option in Settings >> iCloud on your iPhone.