Ubuntu's default Apache configuration can be a bit strange if you're not familiar with how they do it. The "main" site is actually set up as a virtual host out of the box; the upshot of this is that putting your configuration directives in the top level httpd.conf file probably isn't doing what you expect (since it doesn't affect the virtual host).
CGI scripts are enabled by default, with Apache's /cgi-bin aliased to the /usr/lib/cgi-bin directory. If you want to point it elsewhere, edit the ScriptAlias block in the /etc/apache2/sites-available/default file, and restart Apache.
Edit: You're probably better off just putting your own scripts in /usr/lib/cgi-bin (or symlinking to them from there). Other optional Ubuntu packages expect /usr/lib/cgi-bin to be the default script directory, so you may cause other problems down the road if you change it. Alternatively, you could configure a second virtual host with its own script area... or add a block to the default site configuration file along the lines of:
ScriptAlias /mike-cgi/ /home/mike/cgi-bin/
<Directory "/home/mike/cgi-bin">
AllowOverride None
Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
Order allow,deny
Allow from all
</Directory>
Whereby you have a second CGI folder (which in this example sits at /mike-cgi/ in Apache's document tree, and is an alias to the cgi-bin directory in user mike's home area), with your custom scripts in it.
Hope that made sense... if not, keep asking questions until we get it sorted!