It could be the bushings or the struts. If it's the bushings now is a great time to upgrade to poly!
I finally finished mine up (along with the rear disc set-up I've been sitting on for a year) and it tightened it up a great deal.....well worth the hassle/effort to install them.
Try spraying some WD-40 on the bushings......if the creaking stops for awhile you know where the problem lies. You could even do the same thing with the struts, if you can get the WD-40 under the boot/dust cover.