In the first track, I've stuck to the key of C. It cycles through I vi IV V three times and then again but this time with a dominant V chord. So the chords are as follows:
C Am F G (or G7 in the second half)
In the second track I've changed the key to D and it cycles through I vi IV V three times, then changes to I vi I V for another three times. If you compare the I vi IV V part of this track to the track done in C you can hear that, even though they are in completely different musical styles and key, the chord progression has exactly the same basic flavour. Listen to a I vi IV V progression enough times (like I did today ) and you will soon be identifying songs you hear that make use of it.
The chords for the second track are:
D Bm G A followed by D Bm D A
Have fun, and watch out for the incredibly cheesy outtro on the second track!