ISO files are used to burn Data CD's. If you want to share software CD's with someone far away, you can dump the contents of the CD into an ISO file and then transfer the ISO file to him.
For this job, readom from the cdrkit package can do. If you use Windows, download cygwin1.dll and readom.exe, then put them in C:\Windows and start the Command Prompt. Put the Windows XP CD in your CD-ROM (Assume CD-ROM's drive letter is D:) and run the following commands:
readom dev='D:' f='/home/Public/Downloads/dumped.iso' speed=2 retries=8 -noerror -nocorr
Assuming we're using Windows Vista or Windows 7, we'll find the dumped ISO file at
Alternatively, we can use WinImage to dump the CD contents. From the Disk menu of WinImage, make sure “use CD-ROM D:” is checked. Then, select “Create CD-ROM ISO image...” from the Disk menu. If you get an access error, close any Windows Explorer, Media Player or file manager.