If you are using a portable computer (laptop) and connect to WiFi hotspots in different places (coffee shops, office, libraries, public areas etc.) then you can use a cool software tool from WeFi.com -
When you register with WeFi, you can enter your Twitter ID, and then every time you connect to a WiFi hotspot, it will automatically tweet a message about that, something like "SearchJane has just connected the Internet from Starbucks, Union Square, San-Francisco".
It is still in Beta so there are some things to improve, but it is really cool.