To count the number of characters in a cell use the LEN function
i.e LEN(C8) will return the total number of characters in the cell C8 including intermediary spaces.
I suggest you then have another column using the IF function
i.e. =IF(D8>60,"Y"," ") in D8 will leave D8 blank except when the data cell is greater than 60 characters.
SO far as I know there is no way in Excel to change colour conditionally, but try this for size