I'm installing a copy of Oracle on my development workstation because running tests against a remote database is terribly slow. However, it says something about me having to set the loopback adapter as my primary network device since I'm using DHCP. However, my understanding is that this will effectively block all internet access for me.
Are there any alternatives for me here? If it makes any difference, the Oracle install doesn't need to be accessible externally.
I think by "primary network device" it is just meaning in your Oracle config (rather than setting your default route to go via localhost) so I don't think this is an issue. Oracle will bind to 127.0.0.1 instead of your non-local interface. In this case other machines won't be able to connect to your Oracle config, though this is probably not a problem on a dev box, but you will be able to connect fine.
If you need other machines to see your dev install, then you could ask your network people to assign your machine a fixed address from the DHCP pool (most DHCP setups reserve a range of addresses for devices that need to not have their address change over time).
Here is how Oracle says you should install the loopback adapter for a 10g instance on XP.
Installing the Microsoft loopback adapter is quick and easy and (IIRC) doesn't stop internet access.
You might want to consider running Oracle within a vm. The Oracle install is quite large and complex and to have it sitting on your dev box may make it complicated to administer.