I probably would use scanf and then & with 0xff, 0xff00, 0xff0000 and shift them to get the 3 values for RGB and then call [UIColor colorWithRed: green: blue: alpha: 1].  Is there a better or easy way to implement it?
The # in front should be optional in the string, and it shouldn't be case sensitive so 3a6ffc should work as well as #3A6FFC.
 
     
    