With awstats you can create great statistics and graphs about the access of your website. If you want to use more than one logfile in a configuration file, you can use logresolvemerge.pl which is included in the awstats package.

i.e.:
LogFile="/path2/awstats/tools/logresolvemerge.pl /var/log/apache/access_log /var/log/apache/another_log |"

Test your configuration:
/path2/awstats.pl -config=sitename -update