I will try to explain to the best of my ability. Before I do, you can choose to use this guide.
http://forums.afterdawn.com/thread_view.cfm/213943
Its much easier than what I have.
Now this is my way of doing things. If you want to go with my setup. This is a longer way of doing things, if you bother to go with it.
You don't need a FTP program to do this, just Internet Explorer since it has built in FTPing ability. Make sure you are loading a hacked dashboard off a CD because it does not seem to work on a installed dashboard for some reason. This is if you are going with my setup. You can do this by downloading EvoX from somewhere. (I don't know the legal status of telling where you can get it, so I trust you know where to find it). You are going to need a router if your computer is not nearby, if your computer is, all you need to do is buy a Ethernet PCI card you can install into the computer. You can't share your main Ethernet connection from the computer to the Xbox since that will not work. If you have a wireless modem already, then you are all set then. Just use a 2nd Ethernet cord, from the modem to the Xbox.
You can use Auto Installer Deluxe as a FTP program as well if you can't find EvoX. Its much easier to find that Evo. You don' need to install anything with it, just leave it at the screen, and your connection to the Xbox instantly opens for just leaving the disk inside the xbox. Press R3 if you get annoyed by the music if you hear it for too long.
Make sure you have a extra Ethernet cord, and connect it from your router or 2nd Ethernet connection to the Xbox.
Now load up EvoX or Auto Installer, and it should show you your IP address somewhere. I can't remember where, but you will see it. Now type that in IE Explorer.
ftp://xbox:xbox@ Your Xbox IP address here/ (no spaces of course)
It should connect to your Folders. Use the E folder to dump stuff there.
I hope this helps.