Help setting up Airport Exposes

Hi, I'm finally taking the plunge into computer audio and have a question. I want to put my music and Itunes on an external usb drive, hook it up to a router and feed the AE without involving a computer. Can that be done our do I need to have my laptop involved somehow?
I'm not 100% sure I have understood your question, so forgive me if this answer misses the mark. You will need an operating computer in the process. The external drive can be the storage container but it will not run an operating system (OS). I have three AEs connected to different systems and use an old surplus PC with Win7 and iTunes to stream the music I have stored on a network drive. An internal or external USB would do as well. I then use an iPad with the "Remote" app to control iTunes on the aforementioned PC. Works like a charm and allows me to turn the different AEs on/off and contol volume individually as well.
Not to hijack the conversation, (I'm going to need an external hard drive soon as well), but with all the talk about high-end USB cables: is "beaming" the data across the room better or worse than via a cable? Fascinating to think about.

You answered my question exactly, thank you. It looks like I will have to run a PC to make it work. It would have been nice if that wasn't necessary. What minimum specs do you recommend for the PC? Right now I'm running a netbook on XP with limited horsepower. Thanks.
Glad my answer was on point! As far as the PC goes, you can get away with a really basic low end machine--all you need to be able to run is the OS (windows) and iTunes. iTunes isn't very intensive at all and I think you could probably get the netbook to work fine. Otherwise and old surplus PC ought to do just fine.
Thanks for the added info. Nice to learn Itunes doesn't make a lot of demands. In my neck of the woods CL has tons of 2_3 year old laptops for practically free. One of them should be able to do the trick.