Richard Iarossi posted about the iPad2 external keyboard. Since I couldn't add a photo to my comment, I'm adding a post:
This is a basic Apple wireless keyboard that works well with both the iPad and the iPad2. My son had bought it and didn't find any use for it, so I borrowed it from him. 95% of the time I use the screen keyboard and it works fine. If I'm going to be typing all day long, such as at a CyberStar or CyberPro conference, or when I plan to spend a couple of hours steadily writing/typing, then I'll use the external keyboard. Yes, it's an extra piece to bring along, but it's generally only when I travel, and I still take up less space with my iPad and extra keyboard than when I took a laptop, heavy charger, etc. I haven't used my laptop since getting the iPad, which I find more indispensable each day.
Traveling? I'm ready to go, since my iPad is always with me. I'll usually take my Kindle as well, but I wouldn't need to.