I did a dual boot several months ago just to see if I could. I had Lubuntu on the machine and then installed Mint. I screwed up a little, the machine has a 40GB hdd and I (unknowingly) gave mint only 10GB and left Lubuntu at 30GB. I ended up prefering the Mint version and I use it all the time.
Is there a simple way to go in and change the partition sizes?