I recently upgraded an XP machine AND a Vista (32) machine to 7.
The Vista I upgraded to the 64 bit 7 using a program called PC Mover Upgrade Assistant by Laplink
that moved my settings AND programs to the new OS. A few I had to re-install but so far most of them
are working well!
I used the same program for the XP machine and even though I was upgrading from 32 bit to 32 bit,
there were problems with the OLD XP settings that screwed it up and I had to re-install the programs manually.
As there were only a few programs on the XP machine, it wasn't a big deal. The Vista machine has almost 200
programs and games so I was glad that one worked. Having had problems with the older XP system for some time, I was kind of expecting it to fail.