The Freedom of Information Act is still one of the most powerful tools in a reporter's toolbelt. Since it has been a long while since the WatchDog published a list of useful FOIA helpers, we hereby offer our short list.
The Reporters Committee for Freedom of the Press 
After 38 years, RCFP is still the best all-around source for reporters on FOIA and other information-access issues. Start with their First Amendment Handbook  and their How To Use The Federal FOI Act.  For the faint-hearted and newbies, there is the famous on-line automatic FOIA Letter Generator.  And much, much more: guides on state-by-state FOI laws, reporter's privilege, access to places, military dockets, secret courts, and even Indian FOI law.
First Amendment Center 
The Gannett-funded Freedom Forum's First Amendment Center has long been a resource for reporters seeking government information. They sponsor an annual FOI Day. They are especially strong on Supreme Court cases and teaching the First Amendment in schools. They also aggregate FOI news and put out a range of specialized FOI publications.  "How to File an FOIA Request." 
National Freedom of Information Coalition 
For years, the NFOIC led the charge at the state level, giving grants and support to organize FOI groups in most states — a hard job. Recently, it was moved to the University of Missouri at Columbia's School of Journalism,  where it is housed. It is directed by Missouri J-school Prof. Charles Davis, who has spearheaded FOI activities  there for a long time.
Society of Professional Journalists, Main FOI Page 
The SPJ supports a robust FOI program that focuses on practical tips for working journalists trying to unlock government information. Many of these tips are in an online/print publication called Open Doors.  Also check out the SPJ FOI Toolkit.  SPJ also runs Project Sunshine, to support journalists at the state level. Find help in your state here. 
The Brechner Center for Freedom of Information 
Located at the University of Florida's College of Journalism and Communications, the Brechner Center features possibly the best database  on state and local open-records and open-meeting laws — as well as openness ratings. The Brechner Center also tracks state-level FOI legislation in a timely way. Together with all its other FOI programs, it offers local reporters a short-cut to understanding the local rules.
U.S. Justice Dept, Office of Information and Privacy 
Justice's OIP is the office that has traditionally overseen all federal agencies' compliance with the Freedom of Information Act. Thus, they are one of the very best sources on FOI law, and a gateway to information about FOI rules and performance at individual federal agencies. If you want to get into the legal fine points, try OIP's FOIA Reference Guide  and the Freedom of Information Act Guide.  FOIA lawyers (and others) can track the latest case law at OIP's FOIA Post.