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)
Find Wi-Fi Networks with VirusBarrier X6
If you're in a location with multiple Wi-Fi networks, it can be hard to figure out which is the best one to connect to. VirusBarrier X6 can help - open the program's Network window to view a list of available Wi-Fi networks, complete with the name, channel, and signal strength of each.