I'd suggest checking the "gateway" and "DNS" settings in the Red Hat network configuration when this happens, and also when it works (though the fact that it's intermittent is puzzling -- but maybe the failure is an shortlived one somewhere between and inclusive of your Windows box and the outside world, and perhaps the reboot simply passes the time while this clears itself!).
gateway and DNS settings? I'll have to get someone to talk me through this on IRC, perhaps on Monday.
Hmm! Where do you live, where will the WiFi hub be, and what do you think its range is likely to be? (Sorry to be asking questions rather than helping with your query -- which I can't, I'm afraid -- but I'm very interested in WiFi possibilities out here in deep Fenland ... ).
A BIG FAT pipe is running between Peterborough and Nottingham which is being tapped off and coming from Peterborough to Stamford where wireless will begin . I went to a meeting the other week with the company who want to start the service, but it's still in the early stages. Their main focus is providing broadband (wideband) to rural areas, so you COULD be in with a chance depending on where you live and how far they're planning to take the service.
Ben