It's iPhoto Savvy
I have the power shot SD800 IS and it works fine with leopard. I have 10.5.5 on my iMac. When I plug the camera into a USB port iPhoto automatically opens and asks me if I want to import the photos. I have not had a problem.
I did find this on the canon website in the FAQ for the A590-IS (Sorry the link would not paste in correctly).
Issue: What driver do I need to install my camera on Windows XP or Mac OS 10.1 and up?
Solution: This camera supports PTP no driver is required
This camera supports the PTP (Picture Transfer Protocol) standard. Driver files for cameras/camcorders that support PTP are supplied by both the Windows XP, Windows Vista, and Mac OS 10.1 and up operating systems thus allowing true "plug and play" operation.
Simply connecting the camera to the computers USB port and turning the camera on in playback mode will cause the computer to automatically find the device and install the necessary driver supplied by the operating system. No Canon provided driver is necessary.
Hi, all. we just got this for Christmas

, and I'm getting acquainted with the 590 connecting it to a new MacBook (Leopard 10.5.5).
iPhoto recognizes the PowerShot on plug-in as Bodine said. Note that only one logged-in user can access the camera at a timeafter switching users, you'll need to unplug and replug USB. In this way, you effectively create backups by downloading from the camera twice if you wish, before deleting the originals from the memory card.
iPhoto is probably much better to use than the Canon software, but I really won't bother to find out if that's actually true. One thing that iPhoto is great at is knowing you took more pictures on the same memory card. It'll download only the freshly added bunch.
I got my previous digital camera a long while ago, so I'm practically new to it, so for fellow newbies, invest in AA batteries, or rechargeables, or hybrids. This camera is an "electron-guzzler". You'll also want to pick up a much larger memory card than what is supplied right away, and of course, consider investing in eye-fi. Very very
