To view your imagery faster in applications that don't support ECW or ECWP, you can install the plug-ins or viewers below:
ER Viewer
ER Viewer is a free, easy-to-use image viewer featuring interactive roaming and zooming with very large JPEG 2000 and ECW files. It can also read most other common file types. Installing ER Viewer also lets you embed large geospatial images in your Microsoft Word documents.
ArcGIS® 8.x and 9.x ECW JPEG 2000 plugin
ArcPad® v6.0 ECW Plugin
ArcReader® v8.x / 9.x ECW Plugin
ArcView® 3.x ECW plug-in
AutoCAD 2000/2000i/2002 Family plug-in
AutoCAD 2004-2006 ECW JPEG 2000 plug-in
AutoCAD 2007 / 2008 / 2009 ECW JPEG 2000 plug-in
AutoCAD® R14 Family ECW plug-in