On your web panel under "Domains>Manage Domains" you'll find a table of all your domains and subdomains (you may have to click on the control/button to show subdomains. Click on the DNS link for the domain or subdomain you're interested in. That will take you to a screen which will show the DNS entries for that domain/subdomain. This will give you the IP address for each domain or subdomain you want to host at Dreamhost.
One thing to keep in mind is that each domain or subdomain hosted at Dreamhost could be assigned a different IP address, though many of your domains/subdomains will end up with the same ones. Thus, the * record at easydns is likely to not work for every subdomain.
One experiment you might try is adding NS records for * with ns1.dreamhost.com, ns2.dreamhost.com, and ns3.dreamhost.com as value. Normally, you wouldn't use a wildcard but would create NS records for each of the subdomains you wanted to host at Dreamhost. I'd be interested in hearing whether wildcard delegation works.
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