Expect HELL - Just kidding

Grab a room phone or guest book for your dialing instructions. If room phones have speed dial buttons get a digit grabber to find out how they are currently programmed

Contact the PMS vender (if they have one ) to see if they can integrate with PBX- if they are not using PMS make sure you read up on lodging and run your tests with the console before cut over- check in/out, room restrictions,maid status ETC.

Spend time on the ARS and make sure it is tight ( not alot of wild cards ) this will prevent service calls with toll fraud or Call accounting issues.

Set up direct to ARS for Credit card machines,fax's

Ring down circuits for lobby phones

Keep looking here I am sure you will get some more good suggestions here.

Good Luck

Alex Kroger
Pinnacle Communications Corp
Mitel/Hitachi
Nationwide Hospitality Provider