San Francisco (IDGNS) - With at least one municipal Wi-Fi project being proposed or abandoned seemingly every day and big carriers like BT Group turning to their subscribers' Wi-Fi routers to make Wi-Fi available, it's hard to know exactly where you can get online these days. But a T-shirt going on sale late this month could solve that problem for you and everyone around you.

The Wi-Fi Detector Shirt, which the online store ThinkGeek will sell for $29.99, has glowing bars on the front that light up in waves when there's an IEEE 802.11b or 802.11g network in range. As with a network strength indicator on a cell phone or PC, more bars light up as the signal gets stronger. A cartoon of a classic radio tower and the simple expression "802.11" say it all for people who are looking for this kind of thing. ThinkGeek employee Ty Liotta developed the shirt, which is only available in black.

Until Power Over Ethernet (IEEE 802.3af, but you knew that) goes wireless, a glowing, network-detecting T-shirt still needs batteries. The three AAA cells for this one are concealed in a pocket sewn inside the shirt, according to ThinkGeek. When it's time to wash the shirt, you can take them out and then peel off the glowing decal, which is attached to the shirt with hook-and-loop fasteners. A ribbon cable concealed inside the shirt links the batteries to the decal, and it can go through the wash -- as long as you hang dry the shirt.

One thing the shirt can't tell is whether the network in range is open or encrypted. It also can't detect the very latest certified Wi-Fi technology, 802.11n Draft 2.0, which is several times faster than 802.11b and 802.11g networks. There aren't enough of 802.11n networks yet, explained Jennifer Kuropkat, a spokeswoman for ThinkGeek, in Fairfax, Virginia.

BT on Thursday became the latest service provider to let ordinary home broadband users share a portion of their Internet connections with the public using software from Fon Technology SL and a Wi-Fi router. The carrier hopes users of the free service will flood suburban streets all over the U.K. with wireless Internet signals. However, Wi-Fi is invisible to the naked eye.

Asked whether the Wi-Fi Detector Shirt will solve a critical problem for users, Gartner analyst Ken Dulaney said, "Probably for a very few people in the world, yes."