First question is how long did you wait? There are 2 delays to contend with here. First, the panel delay, you make a request and it's then pushed out the server. The panels usually say's it takes 10-15 minutes, but I've seen it actually take a little longer but usually less that 20 minutes. The second delay is DNS propagation, that can take anywhere from a few minutes, but usually 12-24 hours, and as long as 72 hours. If you can bring up the domain in your browser and see the default "Dreamhost coming soon" page then DNS propagation has reached you.
As for hot to connect to the server: http://wiki.dreamhost.com/FTP