If you've never been to a Free-Net-like place, you might want to visit CapAccess in Washington, D.C. where the login is: guest and the password is: visitor. And here are some CapFolks' Home Pages.
Here's an article on the topic of Freenets that I wrote for a recent issue of Matrix News.
A remarkable story of courage by a fellow named Jaime Fradera whom I happened to meet one day on the Denver Freenet, a system I've almost never used.
If you want to leave the U.S, try the National Capital Freenet in Ottawa where the login is: guest. There are already Free-Nets in Finland, Germany and the Netherlands and down the road, ones are scheduled to come online in Italy, Ireland and the Philippines...and no telling where after that.
You can reach a great many FreeNets and Community Networks via the Free-Nets Home Page.
If you'd like to visit a free public access UNIX site, try aburt's Nyx, Spirit of the Night. An assortment of further community networks can be found using the Library of Congress. And another route to a large number of community networks is through the Morino Institute.