Can I still just dial the 4 digits to call another phone on campus?
Yes.
Do I still dial 9 for an outside line?
No. And you don't need to dial 1 for Long Distance either. Just dial the 10 digits.
Can I still dial "Pound 4" to pick up calls?
That's changed a bit. Telephone Services can still set up a Call Pickup Group for you like before. Then you pick up calls by dialing "Star 58" and the four digit number of the phone you're picking up for.
How do I set up Voicemail and check for messages?
Dial *86, or if you have a VVX350 or VVX450 phone, press the "Voicemail" button. 
The first time you will be instructed on how to set up your voicemail account. Thereafter, you dial the number (or press the "Voicemail" button if available) to check for messages.
How do I change my ringtone so I can tell my phone from others in the suite?
Press the 'Home" button 
and scroll down to "Settings" (selection 5 or 6 depending on your phone model).
Now slowly press 141 to see the different ringtones. Use the soft keys to Play the tone, then Select the one you want.