Based on the behavior you describe, I bet you are on an Intel based Mac. In a note, the Tab sequence should be Title > Date > Time > Timer > Text Field. Especially on the Core Duo machines it skips several of these. However, there is a way to restore correct functionality.

Quit Now Contact and then do a 'Get Info'(CMD + I)on the Now Contact application file in your Applications folder. There will be a checkbox beside the text 'Open Using Rosetta'. Check that, close the window, and reopen Now Contact. Now the Tab functionality should be correct.
Don Norcross
Technical Support - Now Software Inc