A free open source firmware that can be loaded onto a compatible wireless router and used to create a hotspot to share your Internet connection.
See "Create Your Own Hotspot (Using DD-WRT)" on "Wi-Fi Planet".
See also"Public Wi-Fi Hotspots" in the Quick Reference section of Webopedia.
See also "Wireless Tips for Road Warriors" in the "Did You Know...?" section of Webopedia.