It should be noted that there is NOT a upgrade process for Windows XP to Windows 7. You will need to capture the profile from the machine, install a clean copy of the new OS and then deploy the profile back to the machine. Therefore keeping the end users information.
Information from Microsoft on OS's that can be upgraded to Windows 7
Therefore in order to do this Migration and preserve the users data you will need to use one of the several migration tools available, depending on how many machines you are attempting to do this with, as to which you select.
1. Windows Easy Transfer service.
This can be used to transfer the users data from their "old" machine to their "new" windows 7 machine. (this is a simple manual transfer process)
2. User State Migration Tool from MS
This can be plugged into the LDProvision system to perform the profile capture - and then after the windows 7 image (clean install) has been preformed then it can redeploy the profile of the user back to the Windows 7 system
What is captured and returned to the image will depend on the settings you set for the USMT.
3. The LANDesk Profile Migration tool - details on setting up this can be located here;
I hope that this covers the questions you have on the setting up of the upgrades.
Windows Vista can be upgraded, but if you use the same processes as above you should be able to provide a nice new fresh install of the new OS.
(Note: that any software that is present on XP and needed on the Windows 7 system will need to be reinstalled seperately, either via provisioning or software distribution after the application of the OS image.)
The information Stephen provided on USMT is from version 3. Below is the MS link for version 4 which gives you the option using hard-links. You should be able to capture the profile/settings using the hard-link option then image using imagex(using the option to preserve the hardlinks) and the load the profile information back in without ever actually copying/storing it off the machine. We are not quite that far in our testing so I cannot tell how well it works. We have the USMT and windows 7 provisioning using imagex working separately. Next week(in theory) will be taking the next step.
USMT 4 user guide