Greeting iPod Guru's...

I am hoping someone knows a good way to transfer songs from one iPod to another.

I was able to do this from my old iPod to the newer iPod Photo via iTunes, and it was easy and painless.
Now, I got an iPod Nano and was hoping to transfer whetever would fit out of the iPodPhoto into the Nano, using iTunes, just like I had done with my previous iPod's, but alas... no dice!
I transfering some files using the windows explorer, but what a pain!
There must be a better way.

If you know how, please post!

Thanks in advance,

Alex.