Simple..
1.open your Safari browser by tapping on the Safari icon, normally located on your iPhone Home Screen.
2.Once the Safari browser window is displayed on your iPhone. Type in www.blogger.com and tap on the Plus button located at the bottom of the screen to add as a Home Screen icon.
3. Then click on ADD to HOME screen
4. Edit the title to Blogger and click ADD
5.You should now be taken back to the main Safari browser window. Click on your iPhone's Home button to return to the Home Screen. Your new icon should now be displayed.
Also if you want to add photos to your blog.. you can do so via picasa! Cool!
There you go free blogger app! You can do this too with your other favorite websites..