UPDATE- Now with links that work.  Stupid idiot.

If you’ve been left scratching your head about why the iPhone 3GS can be so awesome in many respects, but why it sucks in terms of its WiFi, you’re not alone. A few triangulated tests here have shown extreme variability, and you may wish to check out this very brief research paper before handing the phone in to Apple.

PDF format.  Download the report