Well I fell into being involved with a rally TV show ( I was setting up in car cameras for the Speedvision show) through an acquaintance and then started taking pictures, which got me noticed because of my shooting style, and got me gigs as team photographer for Hyundai USA, Subaru Canada, the sanctioning bodies and a Rally Magazine, so I got rides in the top open class cars (400hp AWD) on occasion when the teams were testing.
I competed as a co-driver when a friend of mine asked me to do it, which was in a Nissan Sentra SER with 150hp and in some ways that was scarier than in the more powerful AWD cars because you had to keep your momentum going because of the lack of power and grip so the driver didn't slow much for the corners, which was a bit disconcerting.
If you want to get involved the place to start is www.rally-america.com which is the sanctioning body and www.specialstage.com is an independent forum (word of caution, there can be a lot of political infighting on this forum and there is a lot of old curmudgeons that don't want to see the sport grow, etc)
This me as meat in the seat in one of the Subaru Canada Cars
http://www.mjswebgallery.com/rally_2002-06/images/2003-72.jpg
From inside one of the Hyundai's but this one production class version, so does not have all the bells and whistles (I am on the right LOL)
http://www.mjswebgallery.com/images/rally27.jpg
Here is a link to a pile of pictures I have taken over the years Rally pics 2002-06