Thanks for nuthin', AT&T
Still playing catch-up because my DSL internet connection was gone most of the day. A month ago, AT&T Tech Support convinced me it was my wireless router, so I schlepped out to the Apple store at Crocker Park and traded it for a new one.
Fast-forward a month and the same problems are back, and not for the first time. What are the chances of a brand-new router having the exact same problem as the old? Not likely.
Which means that the off-again, on-again connection is AT&T's fault. Seems to happen on rainy days, which includes most of today. A quick check on Google shows that I'm not alone with this issue.
I'd be mighty unhappy with AT&T now if my router hadn't been under warranty. Apple gave me a new one no questions asked. Now I just have to hope it doesn't rain.