Here's one possbile solution - one of the the fastest/easiest way is to place object 1 where you want it. Hit the + key on the numeric keypad to create a duplicate right on top of itself and then drag that to where you want the ending object to appear. Click on the Interactive Blend Tool and then click on the first object and then (while keeping the mouse button held down), drag over to the ending object and let go. You'll have the default number of items "blending" between the two objects (it's 20), but you just alter the amount in the Property Bar and it will change automatically.
Now this does not let you specify the spacing in between the items - it will always make them equi-distant.