android.R.layout.simple_list_item_1 is used to format your list with one TextView in each row. This text is large, white and centered vertically.
android.R.layout.simple_list_item_2 is used to display 2 TextViews in each row. The first (android.R.id.text1) is formatted the same as in list_item_1, and the second (android.R.id.text2) is smaller, gray (#CCCCCC) and under "text1".
Please refer to this thread:
http://www.anddev.org/queue_and_display ... t5338.html