I find myself constantly responding to email and SMS from my BlackBerry with the same messages. I have tried a few of the canned response and template programs in the past and am currently testing out Snippits from Eclypse IT Solutions.
Snippits just adds a item to your menu in each app. You click on that option and it will let you select from templates and text to automatically insert into the email. It could be anything from a signature to a message telling the person to contact the support line. I will be giving it a spin and I will report back it if turns out well!