Here are some other sites dedicated to visiting ballparks and minor league baseball:

The Gibbs Ballparks Page
Jim Turner's Travellers Guide to Minor League Baseball
Ballparks and Roadtrips
Frank's Ball Parks
Tom's Minor League Ballpark page
Mike Castro's Fields of Dreams
Minor League Ballpark Photos
Brian Merzbach's Ballpark Photos and Reviews
Charlie's Big Baseball Parks Page
Two Steps Away
MLB Road Trip 2001
Digital Ballparks
Baseball Pilgrimages
David McCann's Baseball Games
Minor League Baseball The official Minor League Baseball homepage

Baseball Ink
SABR - Society of American Baseball Research
Professional Baseball Player Database
Netshrine - Information about baseball related websites - Minor League Baseball History
A fan's guide to the Midwest League
The Kitty League
Cardinals in the Bushes
San Francisco Seals
The Alabama-Florida League
Oakland Oaks of 1948
Two Steps Away - Photographs of the Eastern League
Ohio State League
Suite 101 - Prospects and the Minor Leagues
Hogs in the Minors
Visalia Oaks Booster Club
The Minor League Ballpark
Our Sports Central
Sulphur Dell - Former home of the Nashville Vols
Love of the Game - A Baseball History of the Newton-Conover Twins
Blue Ridge League
Minor League Ballpark
Minor League Baseballs