Account subdomains with wildcard DNS

Hello,

I've got an application that uses subdomains to identify accounts (e.g. account_one.example.com, account_two.example.com), and I want to put it into production. At the moment I have my domains hosted with Dreamhost, but I haven't decided on the server yet (I'm leaning towards Amazon EC3 at the moment).

Does anyone have any recommendations on how to best deploy this? It appears Dreamhost don't allow wildcard domains, but I was thinking something like dyndns could be of use? If I can configure the domain on a separate service to the application server that would be ideal as then I can change that server without affecting availability.

Any suggestions or comments are very welcome!

Many thanks
Dave