I'm not familiar with the s110, but I have the s230 so I might have a couple of ideas.
First thing that comes to mind is that you will want to get into the "manual" mode and then change your film speed equivalent to ISO-100 (the default is 50). This will increase the sensitivity of the camera to light input, though I wouldn't expect dark pictures on a sunny day under most circumstances.
While you're in manual mode, you might want to try "spot AE" light metering instead of the default "evaluative" mode. This will come in handy if your subject is relatively dark while the area around it is bright (such as shooting at the dark side of a building on a sunny day). Normally, the camera will read light from essentially the entire picture frame and will use some evaluation process (I haven't a clue as to what it evaluates, it may just average several zones) to come up with a decent exposure, taking into account the entire picture frame. If the pictures you've found to be dark are of this type, try the "spot" setting.
Since you've been shooting in the "auto" mode, I don't think that you would have control over the 'white balance' setting. Still, if you experiment in "manual", leave the white balance in "auto" for now, until you get a chance to play with it a bit more.
I have to ask though, just how are you comparing the two cameras? Are you shooting the same scenes with both and comparing the results? Are you uploading the pictures to the same computer and comparing them on-screen side-by-side? The only reason I ask is that sometimes, comparisons are made using dissimilar situations which will almost always give dissimilar results.
Other than all that, I'm out of ideas.