FileInfo.com - The File Extensions Resource

.ICA File Extension

File Type 1	Image Object Content Architecture (IOCA) File (Most common)
File Format	File
Common?	No
File Description	Graphics file used for multiple applications; often used for creating icons
Program(s) that open ica files	Mac: XnView Windows: Graphics Converter Pro; XnView

File Type 2	Citrix ICA File
File Format	Proprietary File
Common?	No
File Description	Independent Computing Architecture (ICA) file used by Citrix application servers; contains configuration information for connecting to different servers; can be edited with an ICA Client Editor or a basic text editor.
Program(s) that open ica files	Mac: Citrix Presentation Server Client; ICA Client Editor; Any text editor Windows: Citrix WinFrame; Citrix Presentation Server Client; Citrix Easy Connect Manager; Any text editor Unix: Citrix Presentation Server Client; Any text editor

Information from FileInfo.com - The File Extensions Resource.
http://www.fileinfo.com/extension/ica