Only the first gen, and if you haven't updated the firmware on the ipod touch to 2.x:
If you have an iPhone 3G or have upgraded your iPhone/iTouch to firmware 2.0, SharePod is currently unable to edit any music. Apple has locked the new versions from 3rd party applications. However, you can still copy music from the iPod to your computer.
http://www.getsharepod.com/help/iphone.aspx
I guess one-way is better than no-way, but still ...
There's also something called rockbox that is open source and supports ipods (as alternative firmware for them) but I have no idea if they support the ipod touch or not. The web site hasn't been responding.
update: their page still isn't up, but google's cached page says it's not for the ipod touch.
-David