I just googled around for a way to share your external hard drives in Snow Leopard over a wireless home network and couldn’t find a straight answer. But, motivated by my girlfriend using my iPad until I could get to the bottom of things, I figured it out. Here’s what I did:

You need to be using either,

1. Airport Extreme,
2. Time Capsule,
3. a wireless LAN created using internet sharing via OS X (this is what I’ve got)

It’s really simple to set up:

1. Go into System Preferences and open up the Sharing Pane
2. Check the box next to the File Sharing service.
3. Click the + icon under Shared Folders.
4. In the Dialog that pops up, select the external Hard Drive that you want to share over your home network. (Or any folder you can see for that matter).

To access your newly shared Hard Drive over your home network:

1. Open Finder on your Mac of choice.
2. Open the Shared tab in the left column of Finder.
3. And, you’re off to the races! I’ve even been able to stream video without a problem and my HD is connect over USB.

Hope that helped. Feel free to email me with any questions.