Offer your Mac users an auto-update facility by using Sparkle

It's difficult trying to convince your users that software is dynamic. As a magazine company, we offer full commercial software to download. All legitimate commercial software tools. However, as software is dynamic, it can perform differently across various PCs, depending on your operating system and installed apps. What works effectively on machine may cause an instant blue-screen on another. One solution would be to build an auto-update facility in to your software so it enables the end-user to have the latest installed version on their PC.

Sparkle 1.5 is a free Mac developer toolkit that enables you to build in an auto-update facility within your Mac apps, so the end user can see if a new version is available, read the release notes and choose to install now, later or not at all. It's a free development toolkit, so there's no reason why you shouldn't give users this option.

Sparkle link.