The color of blind man's hat is Red. 

It is sure that the first man saw either both Red hats or
one White hat and one Red hat. There are 6 such possibilities: 

         1)  R  R  R

         2)  R  R  W

         3)  R  W  R

         4)  W  R  R

         5)  W  R  W

         6)  W  W  R

In all above possibilities, the first man won't be sure of
the color of his hat. 

Now, the second man knows that the first man saw either both
Red hats or one White hat and one Red hat. And, he also
knows that its one of the above 6 possibilities. (like we
know ;)) But he says, "I don't know". That means that (2)
and (5) are not the possibilities as in either case he would
be sure of the color of his hat (Red) by just looking at the
third man's color of hat (White). 

Now, the blind man knows that there are just 4 possibilities
- (1), (3), (4), (6) - and in all, the color of his hat is Red.

Let the three be A, B , C
1. A sees the other two as either Two Red or One Red and One White
2. B knows that B's and C's Hats are as in #1. Had C been White B would have 
surely said his Hat is Red. Hence by contradiction C is Red.