I've used Lowepro pouches and cases for years, and this is definitely the best pouch series yet. It's very small, but is well padded and you can use a neck strap or belt attachment. I prefer the belt bit myself, as that fits nicely on to a rucksack waistbelt, or even your trouser belt. It's a rugged little thing and does the job perfectly. I use it with an Ixus 75, which fits snugly, including a spare battery and card.
Update: I've now bought more to fit an Ixus 105, 200 and 310, and can say that this little beauty fits them all, albeit tightly with the 200 and 310, including a spare card and battery. You don't need to go up to the bigger recommeded Lowepro case for the 200 and 310, which is good as I like my cases to be as small as possible.