Oh, and there is this method too.

fc
Compares two files or sets of files and displays the differences between
them


FC [/A] [/C] [/L] [/LBn] [/N] [/OFF[LINE]] [/T] [/W] [/nnnn]
[drive1:][path1]filename1 [drive2:][path2]filename2
FC /B [drive1:][path1]filename1 [drive2:][path2]filename2

/A Displays only first and last lines for each set of differences.
/B Performs a binary comparison.
/C Disregards the case of letters.
/L Compares files as ASCII text.
/LBn Sets the maximum consecutive mismatches to the specified
number of lines.
/N Displays the line numbers on an ASCII comparison.
/OFF[LINE] Do not skip files with offline attribute set.
/T Does not expand tabs to spaces.
/U Compare files as UNICODE text files.
/W Compresses white space (tabs and spaces) for comparison.
/nnnn Specifies the number of consecutive lines that must match
after a mismatch.
[drive1:][path1]filename1
Specifies the first file or set of files to compare.
[drive2:][path2]filename2
Specifies the second file or set of files to compare.



and WinDiff
http://www.grigsoft.com/download-windiff.htm