Yes it most certainly is.
Some people do not recommend it, but it can and does work.
Office 11 (including FP 2003) installs to a different folder than previous version of Office. During install though, FP2003 will set itself as the defaul target for all of your FP shortcuts in your start menu and your desktop, assuming you may have dragged a FP icon to the desktop for quick launch purposes.
What you can do is create a new folder in your Start, Programs menu and call it Office 2002 (or anything significant) and drag all of your Office shortcuts into it. Or just right click on the FP 2002 shortcut icon and select the option to rename it. Either option gives you a renamed or relocated shortcut to FP2002, so when you install FP2003 it writes a new icon to that version of the program and you still have your old icons pointing to the previous version.
You will find that the most recent version has assigned itself as the default web editor meaning that if you right clik an HTML file and select the option to Edit with FP it will go straight into FP 2003. If you prefer FP2002 or any other program for your default you may have to alter your file associations using Control Panel, Folder Options, File Types.
So the short answer is yes, you can.
Hope this helps.