Unless you are using a beta version of iOS 5, there isn't an easy way to change the e-mail alert tone on your iPhone. I found a way that doesn't cost anything or require you to jailbreak your phone.
Problem: You're sick of e-mail alerts, but you don't want to miss important messages from the office or your family. Solution: MailTones, which lets you assign custom alerts. Rick Broida is the author ...