We dont know why it has taken twitter to give these functionality so late but finally Twitter for Android is now supporting multiple twitter accounts. Also now twitter does not need to refresh again and again as it has implemented push notifications.
There were many twitter apps on android market winning over these two issues with official twitter for android app. But now it has become almost perfect and may those users can rely on the official apps.
You can download updated twitter for android app from the market or just check your phone for the updates.
VIA Twitter Blog