Communicate Coughing -- If you try the Communicate Lite demo mentioned in TidBITS #199, and you leave it connected but idle in the background, it will make a slight coughing noise every five minutes to let you know you are still connected, much as AppleLink does. The reminder helps you to avoid running up a phone bill or running down a PowerBook battery. If you don't like the sound, you can turn it off, pick another one, or increase the time between reminders.
Fun Way to Send Attachments in Mail
If you're working in a file that you want to attach to a message in Apple Mail, you can transfer the file to Mail easily: From the title bar of the file's window, drag the little proxy icon to Mail's icon on the Dock. Your Mac will make Mail the active application and open a new outgoing message, with the file attached.
(If your icon won't drag, the file probably isn't saved.)