Install Mint over a dual-boot XP / Ubuntu installation?

[proxima_centauri]

Nathan,
When you start the installer after you choose the language/location/keyboard layout, the partitioner will load. Instead of selecting the Guided options, select the Manual option. From there, you can choose to manually install Mint, simply select the partition Ubuntu is currently on, and edit that partition so it's mount point is "/" and formatted. You can also specify your /home partition here if you have one. If you need more specifics over which partitions are which, you can run "sudo fdisk -l" in Ubuntu's terminal and post back your partition scheme.
Cheers