Honestly, I didn't even know people tried going that far. I wasn't even aware of this "Wi-Fi" term, even though I have a wireless setup right here (in fact, I'm using the computer in question). =)
1/2 a mile is not a short distance; what kind of area are you in? Is it mostly wooded (I know you said trees) or are there buildings and stuff nearby? Any radio interference?
The best possible thing you could probably do is head over to the Wi-Fi forum at: http://www.wi-fitechnology.com/ and ask them for help.
Also, let us know your results - I know a college student who would drool at the idea of having high speed internet access shot straight to his laptop from his house to the coffee shop he frequents everyday (wipes mouth).
-Ramon http://razor.ramon.com
