If you need to create multiple domains on your localhost for testing purpose, here is what I do:
Create 1st domain as normal.
For 2nd (and each additional) domains:
1. use config wizard to set up the domains, until towards the end
2. on "Select Optional Configuration" screen, check "Administration Server", then you can select a different admin port (i believe you can also simply change the port after config, use config.xml with <listen-address>)
3. after domain is created, edit domain/bin/setDomainEnv.cmd, find
if "%DEBUG_PORT%"=="" (
change the port# to something new, e.g 2nd domain, set it to 8454, 3rd domain set it to 8455 etc...
While i'm at it, here is how to delete a domain:
1. delete "user-projects/domains/your-domain-folder" (or rename it)
2. go to middleware home (c:\oracle\middleware), in domain-registry.xml, delete your-domain entry
3. oh, remember to delete "user-projects/applications/your-domain-name" folder as well.