I am playing with wpmu, thats what wordpress.com is using. with this plugin, people can sign up for i.e till.mydomain.com and redirect their own domains i.e. till.de to till.mydomain.com and my wpmu isntallation will catch this so you use your own domain i.e. till.de but use my services at till.mydomain.com.
does that make sense to you? I tried the long explanation, but your one sentence
Do you want to redirect subdomains of a domain or different domains to your wordpress installation?
could also be simply answered with YES :-)