I only started to do this the other day and found it saves loads of time. I don't know why I didn't do this years ago!
Open your httpd.conf apache config file and find the ServerName directive, add (or uncomment) the NameVirtualHost directive and add a couple of virtual hosts.
BTW, my machine name is 'nineinchnails' in this example.
Then you'll need to add the Directories or they won't have the correct permissions
# add to your httpd.conf file
NameVirtualHost *
<VirtualHost *>
ServerName subone.localhost
ServerAlias subone.nineinchnails
DocumentRoot C:/web/one
</VirtualHost>
<VirtualHost *>
ServerName subtwo.localhost
ServerAlias subtwo.nineinchnails
DocumentRoot C:/web/two
</VirtualHost>
# Directories
<Directory "C:/web/one">
Options Indexes FollowSymLinks
AllowOverride None
Order allow,deny
Allow from all
</Directory>
<Directory "C:/web/two">
Options Indexes FollowSymLinks
AllowOverride None
Order allow,deny
Allow from all
</Directory>
Set IIS to listen to port a different port e.g. 8082 if your going to run apache on port 80.
Amend your hosts file, it's normally in C:/WINDOWS/system32/drivers/etc
# add lines to your host file for your new subdomains with the format: # IP subdomain.locallost # IP subdomain.machinename # For example: 127.0.0.1 subone.localhost 127.0.0.1 subone.nineinchnails 127.0.0.1 subtwo.localhost 127.0.0.1 subtwo.nineinchnails