Look under BlackBerry help (top of the site) in the How To and Faq forum. There's a detailed explanation. The signature will count against your character limit.
Posted from my CrackBerry at wapforums.crackberry.com
This speaks on auto text. I just want my signature to be at the end of all my texts.
Just create a new AutoText. Something like "mysig" and replace it with whatever you want your signature to be. Just remember on SMS that counts as characters.
Are you texting a lot of people who don't know who you are? The only reason I ask is that I have friends who will end their messages with -John or -Mary
And it drives me NUTS. There really is no reason for a signature at the end of a text UNLESS you are using SMS a lot with people who may not have your number saved.