as long as the raid drivers are already installed (ie, you've got the controller enabled already) it shouldn't be a problem
acronis true image can do exactly what you want
it's about £25, buy the download version from their site, then install it and tell it to 'create bootable media'
now uninstall acronis, and burn the iso file to disc, run things like ccleaner to get rid of temp files etc, and disable system restore (takes up loads of space)
now reboot and boot from the acronis cd
this will load the program in a non-windows environment, use this to create an image of the c drive (either store it on an external hard drive / network location / cd/dvd's)
once this is done (cd/dvd's is the slowest method), turn off the pc, setup the raid, turn it back on and insert the original acronis cd
from the software, choose 'restore' then tell it the path of the image file(s) you created with it (ie, insert the dvd's) and it'll take care of it
awesome software
the other day i created an image of c: that was on a raid setup, and restored it to a single drive, with no problems
