Apologies for the very-late reply but mod_nss requires NSS 3.9.3 or
higher. You should be able to retrieve pre-built binaries for most
systems at
ftp://ftp.mozilla.org/pub/mozilla.org/security/nss/releases/NSS_3_10_RTM/
You will also need a more recent version of NSPR. You can get v4.4.1
from
ftp://ftp.mozilla.org/pub/mozilla.org/nspr/releases/v4.4.1/
I wouldn't recommend replacing the versions in /usr/lib with what you
download. The versions in /usr/lib are used by mozilla/firefox and while
NSS and NSPR have excellent backwards compatibility I don't want to hose
up your browser.
What you can do is untar it in /usr/local and then add
/usr/local/nss-3.10/lib (and the NSPR directory) to your LD_LIBRARY_PATH
before starting Apache.
rob