Rooting the Motorola Milestone has been a somewhat impossible task given Motorola locking down the bootloader. I say somewhat because some folks at AllDroid have managed to gain root access on the TELUS Milestone, albeit without kernel access.
A good start is better than nothing and there are some directions on how to root the TELUS Motorola Milestone over at AllDroid. I find the poll at the top quite humorous: “Did this thread help any” with the choices all answering questions with questions… onf of them “Did you brick your phone”? Feel free to try this out yourself, but if you have to answer the question with the question we noted – don’t blame us!