QuickTime 7.6.6 for Leopard is recommended for all QuickTime 7 users and according to Apple brings about "general reliability improvements for iMovie." Additionally, the update addresses a long list of security vulnerabilities related to maliciously crafted audio or movie files that could allow attackers to cause crashes or run arbitrary code. The update is available via Software Update or the Apple Support Downloads page. (Free, 68.63 MB)
Easily Change Firewall Settings in VirusBarrier X6
If you need different levels of protection on your laptop based on location, you can set up VirusBarrier X6's two-way firewall with multiple configurations. Whenever you change locations, switch easily to the firewall settings you want to use from the Intego menu, located in the menu bar. Make as many configurations as you want: for home, office, when you're on public Wi-Fi, and so on.