Travel Technology - How to find 'device address' of phone (Vodafone)?

Occasionally I have need of the 'device address' of my phone. For example, when I registered w/United's flight paging service long ago I needed my AT&T address that went something like ########@mmode.net or somesuch and I had a similar #######@sprintpcs.com at another point in time.

Nowadays, United has a nice little wizard that figures this all out for you based on your phone company - If you're in America. Now that I'm in the UK with Vodafone, I need to figure it out myself. I've googled, I've search the Vodafone site, you name it. I'm exhausted.

Anyone know the convention? :confused:

http://www.livejournal.com/tools/textmessage.bml?mode=details

You'll probably need to sign up for a username at www.vodafone.net first.