Apple Broadband Tuner v1.0
The idea of changing some networking settings in Mac OS X to get better speed from your broadband connection has been around for quite awhile. I've used the donationware Broadband Optimizer on every version of Mac OS X since Jaguar and it's definitely increased my broadband speeds, particuarly on my LAN. Now Apple has jumped on board and is offering a package that provides the same similar functionality. Apple's Broadband Tuner v1.0 is available for download from their downloads page. Apple's version requires Mac OS X 10.4 or later.
Thanks to Tim O. for the tip on Apple's release of this software.
Update: Further reading the comments at MacRumors.com make it seem that this software is helpful primarily to satellite broadband users rather than cable or DSL users. It's for people with high-latency broadband, and most cable and DSL lines are very low-latency. I'm not entirely sure why my LAN speeds increased consistently after using the donationware Broadband Optimizer. As always, your mileage may vary.