OK, it's almost July so I'm entitled to post a new 'question of the month', right? Here goes...
I've recently started a couple of new Drupal 7 sites to complement my host of D6 sites. Since I'm cheap, I installed D7 onto the same VPS where my D6 lives. So far, so good.
I'm looking to use Drupal in multi-site mode in both versions so I now have a folder structure which includes /drupal/sites and /drupal7/sites. All of the subdomain sites I've created in this fashion are working. For the sake of an example I'm going to use fictitious domains abc.com and xyz.com.
home.abc.com points to /drupal/sites/home.abc.com and it works just fine. Likewise, home.xyz.com points to /drupal7/sites/home.xyz.com and it works nicely too.
Right now, both the root domains of abc.com and xyz.com refer to /drupal/sites/default and subsequently point to my old Drupal 6 "catch-all" site. I would rather that these root domains now point to my new Drupal 7 "catch-all" site.
I've tried moving my settings.php files around to make this happen, but here the mix of D6 and D7 seems to be problematic. Since /drupal/sites/default is on the D6 side of things, my root domains are finding no suitable 'default' configuration and keep prompting me to create a new one.
Am I way off target here, or can anyone suggest a simple Apache configuration change that I can use to catch both abc.com and xyz.com and point them both to my /drupal7/sites/default site?
Thanks in advance. Take care.
Mark

Comments
Virtual Host Won't Work
Mark, Good idea. It isn't possible to accomplish what you want on a virtual hosting account. You didn't mention your type of hosting account and just mention the virtual thing just in case it applies to your situation.
D7 sites.php
I think your apache config is ok if apache vhosts are configured with both domains pointing to drupal7, is it the D7 install screen you are seeing? If you are using multi-site with D7 you will need to configure the domains and subdirectories within drupal7/sites/sites.php file to point whichever domian to the corresponding drupal7/sites/whatever.xyz.com subdirectory
so point both whatev1.abc.com and whatev1.xyz.com to the drupal7/sites/default subdir, I think that should do the trick.
http://api.drupal.org/api/drupal/sites!example.sites.php/7
Thanks for the Comments
Thanks guys. To elaborate a bit... These domains are on a VPS (virtual private server) so I have sufficient access to the OS to control the Apache configuration. Unfortunately, my vhosts are , I believe configured with one pointing to D6 (the abc.com) and the other to D7 (the xyz.com) and I need to keep them that way as I'm not ready to transition all the sites to D7, yet.
When I target my D7 'default' site now I'm still getting the D6 'default'. And if I remove settings.php from the D6 default I get the D6 installer.
So, your comments suggest that I'm close...just need to visit my D7 sites.php and perhaps my Apache configuration to see what's listed there.
I'll let you know if I get it worked out. Thanks.
Mark
Resolved...
OK, I found the source of the problem. By necessity, my /etc/apache2/sites-enabled/default configuration has to point to my D6 document root, otherwise the D6 sites I have there don't work. I tried pointing this file to my D7 root and then EVERYTHING (D6 and D7 domains alike) wound up there.
The real problem was that I had created /etc/apache2/sites-enabled/xyz.com and www.xyz.com vhosts configurations with the www.xyz.com version pointed correctly to D7, but with the xyz.com edition still referencing the old D6 document root.
I got the xyz.com configuration file straightened out and all is well now.
Thanks again. Mark.
Mark
apach2ctl -S
good deal, I've had issues like this before with multiple configs loading, and I believe #apache2ctl -S will show what vhost config files are loaded, and on what order they are loading. Glad you got it worked out.