When writing out a text message on the iPhone (or iPod), you may need to go back and correct a spelling mistake that you wrote.  Positioning the cursor in the exact location to make a change isn't always easy unless you know how to bring up the magnifying glass. The iPhone magniftying glass allows you to move and position the cursor exactly where you want it. 

Before I knew how to bring up the magnifying glass, I would just try to get close enough to where I wanted to make a text change, which usually meant I had to delete text and re-type things that I really shouldn't have had to otherwise.  To get around this problem, you'll definitely want to start using the iPhone magnifying glass if you aren't already using it.

To bring up the iPhone magnifying glass to help you position the cursor in just the right spot within text, do the following:

1. On your iPhone, near a spelling mistake or text you want to change, hold down your finger on the iPhone screen for 2 to 3 seconds and a magnifying glass will pop-up.
2. Now just move your finger around to place the cursor in the exact location you want within the text.
3. Once you have the cursor positioned where you want, release your finger from the iPhone screen.

The magnifying glass is extremely useful, especially if you write alot of text messages or emails using your iPhone.

UPDATE: How to Move the Cursor on iPhone using the Space Bar