Here's a list of  things to look for in an agile organization. If an organization calling itself agile doesn't have a significant number of them, it's a clue to look carefully at how things are working before becoming involved. Think of it as a Joel Test for agile. Here are the items, in no particular order:

• continuous integration
• story wall
• regular metrics (velocity, coverage, cyclometric complexity...)
• (promiscuous?) pair programming
  
• TDD
• version control (not specific to agile org, but key nonetheless)
• "one team" (the idea of distributed agile seems to be in question, having advocates and detractors on either side of the issue)
  
• regular demos (with who, the customer?)
  
• planning poker
• coach who removes obstacles that block developers
• daily standups
• retrospectives
• sustainable pace (used to be called "no overtime" or "40 hour work week")
• reference books to support good code: (Clean Code, Refactoring, ...)
• collective code ownership
• pair during interviews
• Got a  Agile Center of Excellence – A one stop shop for Agile
• Learning eco system
• Work flow automation
• Automation tools
  
• Technical Debt Wall, see here and here