Craig mentioned the Asus eee.
I have one and I love it, but you need to work within the limitations that the machine provides.
It's great for surfing the web and the occasional document or spreadsheet etc. IM is fine too. I have a 3 wireless connection, and it sits beside the Macbook in the studio when I'm on the air, and I use it for researching missing information about the tracks I'm playing, IM, email etc.
At home, it seamlessly and wirelessly connects to the LAN, and one extra (and very valuable) use for this is that, because of its size and portability, it's ideal for setting up new routers and stuff when you need a direct connection to the hardware in question.
No worries at all.
Mine is set up with a 4GB SD card that's bootable into Windoze XP Home as well, for those times when I feel like I want to be reminded about just how great Windoze is.
The Xandros distro that's the default install is one of the best Linux distros that I've seen, and for people who don't want to know about OSes and such, it's great. It comes with most everything that you need, and it just works.
Cons: Battery life is less than two hours. It probably will not be coming to N'Awlins with me.
The screen is smaller than I'd like. That's expected, and not an issue. it just is.
Value for money is pretty bloody good, and it's a great machine to carry around and use on a bus or in the train, or wherever. I often use it at meetings to stay online and awake instead of playing Buzzword Bingo.
Whether I'd grab one to take to the US? As I mentioned, it's unlikely to even be packed in my checked luggage, and perhaps it might be a good idea to see what's available in the bricks'n'mortars for when you land in the USofA? That might save you a few hundred at the purchase price, especially given the current value of the Pacific Peso.