I'm having trouble connecting CS3 Dreamweaver to the mySQL db running inside Sun Virtual Box
Does your VBox have access to the outside world? Try pinging google from the vm; if that works ok then do ifconfig (or ipconfig on windows) and see whether your vm has an IP. If it hasn't then you'll need to assign one (or get one via DHCP from your router). Once you've got one, check you can ssh/telnet in. If you can, then you should be able to get to mysql providing there aren't any firewalls blocking the port.
It's easy for the guest VM to get a connection to the host machine's network, but I haven't tried to connect from host to guest. It looks like there's a network interface you can turn on in the guest VM:
http://georgelantz.com/2007/11/27/virtualbox-host-interface-networking-windows-host-ubuntu-guest/
VMWare Player comes with this functionality out of the box, but I don't use it anymore after finding Virtualbox.