If you search on-line, you will find plenty of software that promises to solve this for you, but I was lucky enough to stumble across a couple of utilities that done what I wanted....
One good entry is on Yahoo but I found two independent free sources of software before I stumbled across that site, they are:
Senuti - at least it's a 30 day trial if you just need to copy all of your music quickly
'Image Capture' (visit your Macs application folder to load it), it will copy the photos from your iphone to a directory of your choice!
Now I can sync everything from my Mac back to the iPhone without loosing anything... I'm not sure about the applications (I've used iTunes to right-click on the iPhone and chose 'transfer purchases')
I hope that helps!