I'm using identi.ca in Austria over T-Mobile Austria. The mailaddress is correctly implemented, but the problem on receiving is, that on "first contact" T-Mobile sends a PIN to the sender which should be used in all further mails to the mobilephone address. Cause of that the first SMS (like verification) won't be sent to the phone.
PINs will be invalidated after 60 days of inactivity.
In Europe sms2mail functioniality is mostly available but no one hardly uses it.