The Stanza desktop will let you transfer books to the ipod touch via wifi, but you need to configure the firewall on your wireless router to allow it. I would be far happier if you could share of USB as well. At the moment I am using Stanza to covert books to eReader format and then putting them on a web page to download them to the iPod Touch. Its not exactly an elegant solution but it works ok.
My biggest complaint about the iPod Touch as an book reader is the size of the screen. I think I can live quite happily with an LCD screen (except for battery life issues... the Jetbook would be if it supported something besides straight text) since I often spend 12-14 hours a day looking at computer screens with no issues. My biggest complaint about the Touch and other PDA sized devices is that they are... well PDA sized. A 3.5" diagonal screen is a bit on the small size. I have to use smaller text than I like to get what I think is a reasonable amount of reading between page turns. Even then we are talking about maybe half as much text per page as you would get from a mass market paper back.
For me this is the biggest justification against using the ipod Touch and pda size devices as an ereader. I think a 5" screen would the smallest reasonable size for (me) a device that would be used for the bulk of one's reading.
If Apple was ever to release an UMPC with a 6" or 7" screen, I could easily see myself use it as my primary ereader. Until then I will keep looking at the devices coming out.