how can i set my account up so if i send a sms message to an email acct it will always show my blackberry address not a yahoo

Wirelessly posted (Cingular 7130c: BlackBerry7100i/4.1.0 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/103)

You mean your blackberry email address? Set it to be your default address.

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Advanced options
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Change the default to your blackberry address.

If you want your blackberry carrier address to show up you have to set it as your default email account for ALL messages. You can't just limit it to those that are SMS. I would recommend that you don't send email from that address because you really don't want people to know it. If it ends up getting spam later on it is a big hassle. Also, I have heard that you cannot keep that address when you get a new BlackBerry. If you want that as the default from address because you want the recipient's reply to come back to you instantly, I suggest that you just use your Yahoo account or setup/use an existing Gmail account. Both Yahoo and Gmail are instant push email just like your personal blackberry email address and there is no risk of getting spam at the instant a spammer sends it.