Creating a code to calculate amplitude and phase shift of oscillating curve

Hello mighty Matlab Wizards, I have a large data set which represents two temperature readings. I am working on finding a way to use Matlab to determine the change in maximum amplitudes and the phase shift of the two oscillating readings. If you have any ideas or pointers I'd be very appreciative. Your humble apprentice, -Ethan

(attached in my dropbox are the files in question)

http://dl.dropbox.com/u/30729740/Temp_at_5.txt

http://dl.dropbox.com/u/30729740/Test.m