Yes, you can, but you have to strip the DRM, then convert the format to MobiPocket (via Calibre or however) in order to read it on the Kindle. It's doable, but up to you regarding whether or not you feel comfortable with stripping DRM (technically and otherwise) and converting formats.
I hope to get a Sony (or maybe the new iRex 800 coming out) in addition to my Kindle so I can read library books on it, and AZ books on my Kindle. (And so my kids won't fight so much over the K1 they now share.)