I just discovered Apple’s very helpful iPhone Mail Setup Assistant. A lot of people don’t realize that send email from the iPhone on at&t’s EDGE network isn’t possible with the settings that work in Mail or Outlook that you might use on your computer from your ISP.
I find people very perplexed and frustrated when they discover that some ISPs actually block their ability to send mail from their iPhone when not on their home WiFi network. I used to dig around forums to find the right settings but now with this tool Apple provides officially sanctioned means of accomplishing this psuedo-hack.