Canon actually has a good comparison tool on their website
for their powershot models -- these two models actually list for the same price, so if you look at the features of each and can determine whether or not you need the features of the more expensive one, get the less expensive one.
They're actually fairly similar, the only real differences that stand out in my head:
SX130 has more reach (digital, both are 4x optical), runs off of AA batteries instead of a Canon battery pack, slightly larger LCD (3.0") and seems to have more manual control abilities (shooting in full Manual, Aperture priority, Shutter speed priority)
ELPH can shoot high speed burst , is smaller due to Canon battery pack (i.e. more compact)
Thus, if ELPH is cheaper of the two, I'd probably do that unless
you want a slightly larger camera. They're going to take comparable images for the most part.Edited by MistaBernie - 1/24/12 at 6:16am