Autostitch or
PTGui might be worth getting a hold of and using, rather than Photoshop. Or find a friend with a Canon and Photostitch.
If you can't use a tripod and have to go handheld, I'd recommend choosing a spot to stand where everything's an equal distance away from you. Try not to have any close-by objects, which could cause parallax error problems with stitching. One trick I recommend is to stick a finger into the tripod hole on the bottom of your camera, and then rotate the camera on your finger. You may still have parallax error, but at least you won't have moved the frame of reference.
Use manual settings: lock down the focus, the f-stop, shutter speed, iso, and use a non-auto white balance setting, so all the shots will match when you stitch them.
If there's no way you can get the pano to stitch, you might want to rethink the approach and maybe try something more like
a Hockney joiner collage.
