I have removed the "sent via Blackberry by AT&T" from my signature and it has been working fine. But all of a sudden today it shows up in all the emails I send out through my phone. When I log into the Blackberry Internet Service site it shows the correct signature that I changed it too. I have deleted it and retyped it and it still shows the "sent via at&t" signature when I send an email.
Anyone else having this issue with AT&T?