New England Window Restoration Alliance - a commitment to the preservation and restoration of historic wood windows
Overview of Wood Windows: Tips for Restoration (PDF) - National Trust for Historic Preservation
Preservation Massachusetts - a network of private and public historic preservation organizations
Repair, Retrofit and Replacement of Historic Windows (PDF) - from Preservation Pennsylvania
Restore a Wood Window Sash (PDF) - article from Fine Home Building that explores the steps in restoring an old wood sash
Ask your house painter! Many homeowners have reported that good, knowledgeable house painters have the skills to repair old windows that may be most affordable.
Blackwell's Leaded Glass Restoration
Cleary Window Restoration
FFP Restoration, Waltham
List of Window Repair Shops (PDF)
Masterworks Painting and Restoration Inc.
New England Wood Window Restoration and Repair in Framingham
Olde Bostonian
Sources for Single-glazed Wood Sash to Match Historic Sash (PDF)
Window Preservation Alliance
Window Repair
Window Restoration Products (PDF)
A list of Articles and Resources (PDF)