I was having the same problem after I went to GB. I solved my problem much like you did. My wifi encryption was set to WEP so I changed it to WPA and was able to connect my Droid. Not wanting to go around and change all the other devices in my home to WPA however, I changed my encryption BACK to WEP to see if my Droid would now connect, and sure enough it did. So a quick flip flop of Wifi encryption did the trick, and I didn't have to change over all my other devices. I hope this helps somebody else.
There's different ways, and it does somewhat depend on your router, but the following should get you far enough at least to figure it out: (these instructions are for Windows btw)
First open a Command Prompt (Start menu, quick search for Command Prompt). In the command prompt type in "ipconfig" without the parantheses. In the results that appear afterwards find your Default Gateway. Type in your default gateway # (which a lot of the time starts with 192) into the URL bar of whatever browser you use and hit enter. You should now be on a page that allows you to change various settings of your network, including your security encryption. Just look around until you find it, and it'll probably ask you for your password. This page will be different for everyone depending on your router so I can't help much further, but I hope this gets you far enough to make the changes.