I believe that if you go into User Accounts in System Preferences, click your account, click Startup Items, add iCal to the list, and make sure to check the box beside it so that it is not hidden upon startup, then iCal will appear whenever you log in.
As for whenever you open the laptop, I'm not sure what to do for this. I don't think there's any built-in way to tell the computer to do something when the lid's opened, so I guess that only leaves writing something in AppleScript (possibly, though I have no experience with this), or trying to find a third party app to to the job. Obviously there must be a way to detect whether the laptop is opened, because the OS uses it to turn on the screen or wake from sleep.
Grape
