Check out eBookNewser for a comparison article by Dianna Dilworth.
The two devices look a lot alike and will prove to be direct competitors, especially before Amazon gets in the ring. Both devices employ Neonode technology to enable the touch screen. Both have eInk screens and are going for the reader looking for. Both let you check out library books and come loaded with lots of free eBooks. Both have six inch screens and both are Wi-Fi enabled.
Unfortunately, that article doesn’t give much of an comparison at all, though not surprising given that neither product is actually released. I found a better comparison at: http://blog.the-ebook-reader.com/2011/05/26/kindle-3-vs-new-nook-vs-kobo-touch/ as all we can really compare at the moment is specs.