Absolutely the easiest way to track your business mileage. Press the start button when starting a trip and the stop button when you reach your destination, enter a quick description and you're done! Works with either Miles or Kilometers.
Reports can be emailed to your computer for use in Excel or Numbers or any similar application.

Mail Tools

Mail Tools is a companion to Apple Mail that can manage folders on any email server that supports IMAP. You can add, delete and rename folders. Mail Tools can also copy and paste folders - even between servers or services (from Gmail to MobileMe for example). Mail Tools will configure the settings for accounts on Gmail, Yahoo, AOL or MobileMe automatically - you just need to enter your username and password. For other mail services we are unable to load your current settings from Apple Mail so you will need to enter those into Mail Tools.
We test with Gmail, Yahoo, MobileMe, AOL and several other 3rd parties.Mail Tools is a universal app and works on the iPhone and iPad.
Please note that this app only works with IMAP based email servers, POP3 is not currently supported.