Sorry about the delay ronroam, I went to France for the day.
Anyway, in answer to your question, a couple of hours or so should do it.
Have both towers open, side by side, spend a minute or two seeing what goes where and then transfer one at a time.
The drives are the ones to the front of the computer and the pci cards are horizontal at the rear. They just pull out, after removing the securing screw, and slot into the new quite easily. Start with the top one and work your way down.
From the floppy, Hard Drive and CD-R's, DVD's there is a power plug and a multipin ribbon.
Your hard drive will be on IDE1 and CD/DVD's on IDE2.
If you have more than one hard drive or CD/DVD's then there is one more thing to think about but as you are new to this I won't complicate matters.
If you prefer to have a more detailed plan, please feel free to click on the little yellow envelope, next to my name, and send an e-mail via PCA.