I live in the dorms at my college and connecting to the internet requires both a username and a password, and there doesn't seem to be a way to connect my Roku to this network. Can anyone help?
Are you saying that, to use that Internet connection, normally you would open a browser and then would be presented with a page that requires you to enter ID/Password, and, possibly, accept a Terms of Service before you'd be able to use it?
If so, you may wish to examine the TOS and see if it limits usage in a way that the Roku would violate. That could include bandwidth limits, as well as specific devices.
Some hotels have a similar setup, where a user connecting must enter ID and/or password and accept TOS before use. In those instances, the only option would be to connect via a browser on the computer, then, if your computer supports it, turn on wireless Internet Connection Sharing, and connect your Roku to the ICS. If your Roku doesn't violate the school's Internet connection TOS, then perhaps that method would work for you.