I have 700x32c vittoria's on my bike and i'm wondering if 700x23 or 26c tires could fit in it?
Probably, but we'd have to know the width of the rim to be more definite. I just switched from a 35mm tire down to a 23 mm one using the same rim (couldn't fit fenders with the 35 mm and don't have any intermediate size tires handy at the moment).
BTW, the 'c' goes with the 700 to indicate the rim diameter as a '700c'. The width of the tire is in millimeters and should either be given as 32 mm or just 32, but not 32c.