One of the lessor known changes made in Android 2.2 are the changes to the on-screen keyboard. The most visible change is to the word suggestion bar that appears above the keyboard. After you press space at the end of a word five punctuation marks appear on the suggestion bar that you can select, and when you select one such as the question mark, it is placed properly right next to the last word. With previous versions of Android you have to press the ?123 button to enter most punctuation and all numbers.
The second change to the keyboard is an alternative to the ?123 button for entering numbers and punctuation marks. A row of numbers and punctuation marks appear when you tap and hold the keyboard and slide your finger straight up. To enter a number or punctuation mark, stop your finger over the one that you want to enter and then lift your finger. It can be a a bit hard to use at first, but I find the trick is to pay attention to the character preview that displays, and if you see the wrong item slide your finger left or right until the right one displays.