professional organizations:

• Appraisal Institute
• Central PA Chapter of the Appraisal Institute
• International Council of Shopping Centers
• Urban Land Institute
• Institute of Real Estate Management
• Building Owners and Managers Association
• National Association of Real Estate Investment Trusts
• National Association of Industrial and Office Properties

real estate resources, bulletin boards, industry news:

• PikeNet
• NAR Commercial Source
• AppraisalToday
• Real Estate Professionals' Internet Guide
• National Real Estate Investor OnLine
• Real Estate Zoo
• Inman News Group - Daily Real Estate News

government and regulatory agencies:

• National Registry of Certified/Licensed Appraisers (Appraisal Subcommittee)
• Appraisal Foundation
• Bureau of Labor Statistics
• Bureau of the Census

links of local interest:

• Pennsylvania State Data Center (Municipal demographic profiles from Penn State)
• Lancaster Commercial & Industrial Council (Local Association of Realtors' C&I affiliate)
• Lancaster County Association of Realtors
• Lancaster County GIS (County Property Database)
• Lancaster County Deeds (County Deed Database)
• Realtors Association of York and Adams Counties