With the recent introduction of iOS 5 for iPhone, Apple has added the functionality to assign a different text tone for each contact.  While this works great for SMS messages from other's cell phones, it doesn't work at all for messages received from AT&T's e-mail to SMS gateway.

In my situation, I receive automated text alerts from the office when systems go down.  Because of this, differentiating these messages from a friend asking where we're having dinner is important to me.

When a message is received from the gateway, AT&T marks it as coming from a number simliar to "1-410-000-001".  They do this for one reason - it allows you to respond to the message via SMS.  If later in the day you get another message from the SMS to e-mail gateway, it will increment the number to keep the conversations separated.  

Because there's no consistency in the number these messages are coming from, there isn't a simple way to assign a specific tone when you receive one.  However, about ten minutes of editing a vCard 4 format text file has allowed me to add all 999 numbers used by AT&T to a single contact.

If you want to add this special contact to your own phone, pull up this blog post from your phone and click on the link below.  Or, if you prefer, a) download the file to your computer and e-mail it to your iPhone, or b) import to the Address Book on the OS of your choice and sync with iTunes/iCloud.

http://snoopy.mybnetworks.com/downloads/emailsms.vcf

When adding such a large vCard file to your device, keep the following in mind:

If you use a contacts sync service like that included with Google Gmail, it probably won't support 999 numbers within a contact.  However, iCloud supports it great.  I recommend that you setup iCloud and then go into Settings -> Mail, Contacts, Calendars -> scroll down to the Contacts section -> Default Account -> and choose iCloud.  Once you have imported the vCard, feel free to switch the setting back to your preference.

When you click on the link to import the vCard, your iPhone may act like it is frozen.  This is normal, and I had to wait a moment for the next screen to appear.  In other words, BE PATIENT.