If you want to marshal in 2008, go to http://www.iomttma.com and have a look at the training dates.
If you live off Island, you may be able to get training in your area. If not, and you have to come here for it, get in touch with me, as there are a few of us with spare rooms, who would be happy to put you up while the course is on.. just think, an extra trip to the Isle of Man.. go on!