sony ericsson Z500a Message Centre Number?

Actually, wherever u are in the world, just type these keywords into google.
"message centre number" +your network name
I'm sure you'll find it in the top 3 results.

Sorry for confusing you all with 3 answers!
Pen

pen
August 2010

Damn!!!!!!!! I forgot to add the link. So here it is. Sorry all.
From Pen.
http://www.filesaveas.com/sms.html

pen
August 2010

If ur in th UK, click this link (or copy + paste it into ur browser).
It is a list of numbers for the sms message centres, for the main UK networks.
Hope it is of some help to you.
Peace to all.

Pen
August 2010

I do not know your phone, but try changing the Message Center Number, probably listed under the Messages menu-Message Settings-Text Messages-Sending Profile-Default Profile, or possibly even somewhere in your phone settings menu.
Write down the old Message Center Number in a notebook before you overwrite this, just in case you need to use it again if the new number does not work.
Message Centre Number in my phone is
+447785013998
This works for a Vodafone within the UK.
Or try a similar number from a friend's phone on the same network as your own, for example O2 Genie, Orange, T-mobile.
Let me know if this works
Jim.
jim_mckee_@msn.com

Jim McKee
October 2005