I recommend thoroughly cleaning the tank. Probably boiling water to disinfect any nasties from lizard or in-between owners - no cleaning products though.
As far as moving him into it, I recommend having a read of Day One: Betta - http://www.bettafish.com/showthread.php?t=64078
specifically the information about transferring him into a new tank. It is basically outlined as so:
#1: Setup new tank (substrate, pump, accessories and heater – water conditioner also obviously). Let it all run for an hour or until water temperature is stable.
#2: Put Jake into temporary container (bag with air or plastic container filled with current water)
#3: Place temporary container with Jake on top of water to float against tank – this will acclimatise him to water temp. Leave this for 10-15 minutes.
#4: Place amounts of tank water into current container so you have a 50% old tank water and 50% new tank water mix (don’t let it sink). Leave this for 10-15 minutes.
#5: With a net, scoup Jake up and slowly place into new tank. Release and let him explore or do his thing. Discard temporary container and water – do not pour old water into new tank.
PS. Oops - what DragonFish said ^