I have put a demo script up
here.
The scripts contents follow:
set s [db_string foo "select chr(235)"]
set s2 [ad_space_to_nbsp $s] ;# shouldn't change $s b/c it contains no spaces
ns_return 200 text/html "
[jbe_header test]
$s
$s2
[string equal $s $s2]
[ad_footer]
"
"string equal" thinks they are the same when they result in quite different characters to both NN and IE.