similar vs. exact comparison

I'd like to compare two cells (or more possibly) for similarity vs. exact.
e.g. a cell with the i.d. of 'johnsmith' is not exactly equal to 'johnsmith2'.

Is there a way in excel to compare two cells and see if they are similar?
Maybe even some kind of confidence level flag? (or is this a fantasy?)

thanks,
dave

This may help.

www.exceltip.com/st/Finding_a_substring_within_a_string/874.html