I can not visit localhost with apache on OS X 10.9
Run this command:

sudo apachectl start


That should start your standard apache server software as well as edit the system startup files to cause it to start at boot. Replace start with stop to reverse that change. Your grep shows that httpd is not actually running and there's just the grep process active. You may need to look at the logs if after asking apachectl to start things up, the httpd process doesn't stay running (or even start in the first place).