Aug 04th 2008 Sian
Good morning - Ohayou gozaimasu - (You can drop the gozaimasu but it makes it less polite.)
Hello/Afternoon greeting - Konnichiwa (As trav said ^_^)
Good evening - Konbanwa
Oyasuminasai - Good night
Hope this helps somebody :D

Aug 12th 2008 Kasui-chan
And in Japanese:

おはよございます

こんにちは

こんばんは

おやすみなさい