GoodReader has released a free utility named GoodReaderUSB which, as the name implies to any who haven't suffered a traumatic blow to the head, allows you to connect to GoodReader via USB. The software is free and available for Windows (XP, Vista, and 7) and Mac OS X (10.4, 10.5, and 10.6).
The interface is simple enough, and if you have more than one iDevice you can connect more than one at a time. In my initial testing it worked as expected. The UI is fairly straightforward and allows for drag & drop access, folder creation, and deletion.
GoodReader is available for iPad and iPhone/iPod touch. There's a free "lite" version but the app is easily worth more than the $0.99 asking price. One of the "hidden gems" of GoodReader is that it's not just a reader, but will allow you to download just about any file to your iPhone or iPad by pasting in the URL. I use it for downloading PDFs and then sending them to iBooks on the iPad.