ok, you need to goto the task area (no you cant press enter just park under the marker) and switch the camera views (buttons 1,2,3,4,5&6) on kb not numpad, then it ashould say u unlocked one race, if not get out of the car (button e) look all around it then reenter the car (also button e) and switch cameras again, now u need to go beat the one unlocked race (you may want top get gas first),(during whitch 4x4, low gear, front and rear differential become unlocked) you will need to change each setting at least once, and donot try to early or u will just get a window saying not availible, but before the finish libne all 4 will be availible and u need to use them, and win the race.
themn u return to the task area and this will unlock 3 more races (whitch i havent tried yet cause it was late last night) i assume after beating them one would return to the task area to unlock further races, but this is as of yet unconfirmed.
I hope this will at least help you get going in the career mode and i will edit with any further usefull info pertaing to progressing further in teh game as it becomes availible.
*(NOTE: uninstall the demo first!!!!!!!!, if you have the demo installed you may get a glitched version of the game with only one drag race availible besides the demo races.... if you start career in the snow, you did it right, if you start career in the desert, you have a conflict and need to uninstl the demo, or atleast delete the files in the "motom4x" folder in "My Documents")*