You can't find the information on Starbucks own site, but its wireless network partner MobileStar offers a list of WiFi-enabled Starbucks outlets in Texas, California, and Washington state. Try one today and report back! (Later in the day: I tried the nearest listed Starbucks to no avail. Baristas report not knowing when it will roll out, either, but have heard that it's soon.)
802.11g Update
The 802.11g working group, discussed yesterday, approved the OFDM method over Texas Instruments's PBCC method, of incorporating 20 Mbps+ traffic into the 2.4 GHz range. A vote tomorrow would require 75 percent of the task force to agree, paving the way to finalizing this high bit rate spec.