I'm on my 3rd 3Gs (16) in 3 days - - the 1st one had the same wifi signal strength changes (I had it for 2 months), and only when I stopped in an Apple store this weekend did I see a full 3 bar strength indicated . . . explained my situation and was told it was probably the hardware . . . swapped it out, and couldn't even get 3 bars on the new 3Gs in the Apple store (was told not to worry, as long as it didn't drop to 1 bar) . . . got it home, same problems (dropping to 1 bar even only 2 feet from my Netgear router) . . . swapped again today (although both phone no. 2 and no. 3 worked at full strength in a different Apple store), got it home and same problems - - starts at 3 bars drops almost immediately if I check email or do anything else to 2 and then 1 (and then stays at 1 bar), even only 8 feet from the router . . . did all the Applecare suggestions too, including rebooting, reinstalling, etc., with the same problems between phones 2 and 3 . . . I lot of time and hassle, with Apple reps. saying "they've not seen this problem" and "it must be my router?!"