Create a Milestone
Press the New Milestone button in the main screen. In order to ensure that a location can be found, Milestones will wait until your iPhone has been able to determine a first approximation before letting you start typing. The estimated accuracy of the location, shown in the input window, will usually improve while you type the note.
A character counter, shown under the input field, lets you know how many characters you can still type for a legal Tweet. It's shown in green when you still have room for a picture link, in red when there isn't space for it (so, if you add a photo to the Milestone and try to send it to Twitter, the text will be cropped to make room for a link to the photo). You don't need to bother about this if you don't plan to post your Milestone to Twitter.
Once you are done typing press the Done button. The best estimation of the location at this time will be the one stored with the Milestone. The keyboard dissapears, and you are left in the Milestone's page, where you can edit it, send it to Twitter, add a photo, or delete it.
You can also create Milestones with the New from photo button. It will take you to your photo gallery, where you can select a photo to base your Milestone on. The milestone will be created with the geographic coordinates and the date of the photo. This is a great way to save your notes after the fact: maybe you are taking pictures on the field, and then you use them to build your story in Milestones. And, finally, you share them by mail, photos and notes, so that your friends will be able to see them in Google Earth.
