ANY housing can flood, it's not like a major company such as Canon is going to out out crummy housings for their various cameras year after year. This is an under $200 camera right? Spending serious bucks on the housing (say above $600) wouldn't make a lot of sense unless money is not a factor. I've got 175+ dives on my WP-DC28 Canon housing and no leaks yet. (Doesn't mean it can't happen on the next dive, just that the housings aren't overly prone to leaking.) Rinse the housing well w/ fresh water between dives, working all the buttons and do regular maintenence between trips (try a forum search if you aren't sure what to do) and you should be fine.
I'd also suggest a SB search for exposure info, the question has been addressed numerous times. Take a look at the
Underwater Photography Guide by Scott Geitner, it is a most excellent source for all sorts of UW shooting info!
Underwater Photography Guide
For software, what are you used to now? If you aren't using anything now the software Canon ships w/ the camera should get you going ok. Of course Photoshop would be great if you have it and know it well. A very reasonable in-between answer would be Adobe's Lightroom software. Get used to the camera, then get used to it in the housing, then get used to it diving. That way it will be fun. // ww