Sometimes it would be sweet to know which mobile network operator the phone is using.
Well since there's no direct way to get this information we can do the following:
If the phone supports WMA there should be a system property "wireless.messaging.sms.smsc". By knowing the used SMSC we can guess which mobile network operator is used:
The following should get the SMSC:
String smsc = System.getProperty("wireless.messaging.sms.smsc");
Then "smsc" containst the SMSC as a String.
Now all you have to know is which operator uses which SMSC.
A list of SMSCs can be found here: http://www.gsmtool.de/smslist.html