Somewhat off topic, but saves me from having to post a vanity.
I have a EeePC (701) with Xandros Linux, Firefox 2.0 and Flash 9.0.
The newer EeePC has GNU Linux. I was wondering if anyone knows how difficult it would be to make the switch to GNU Linux and upgrade to Firefox 3.5 and Flash 10??
I can’t answer your question directly - but you have the terminology mixed up. Xandros is a distribution (so that makes sense.) Your use of the term GNU Linux doesn’t. GNU software is part of every Linux distribution. Perhaps you mean Debian or Ubuntu? These are distributions that are FSF blessed (at least Debian is..) and Ubuntu is a Debian progeny.
I think there’s an Ubuntu distribution especially for the EeePC. You might check into that....
I don’t know about Flash, but in most of the Debian based distros (like Xandros, Ubuntu, Mint, etc), you can install Firefox 3.5 along side of the default 2.0 version. You should be able to find it in your package manager.
Then, it’s just a matter of changing the default browser on the system and changing whatever shortcuts you’ve created to use the 3.5 and you’re good to go. Shouldn’t take more than 5 minutes.
From Wikipedia:
Xandros Desktop is a Linux distribution.
I run a variant of Ubuntu on my EEEPC 901 called Eeebuntu (www.eeebuntu.org). That's one option...
Since Eeebuntu is moving away from the Ubuntu base for their next release, I'm probably going to jump back over to Ubuntu 9.10 (just released yesterday) once a particular EEEPC specific app is updated for the release. (www.ubuntu.com). They should have Firefox 3.5 included and Flash 10 available through the OS Add/Remove function (Flash isn't included on install because it's not Open Software).
I would suggest also taking a look at the ubuntu forums (www.ubuntuforums.org) and the EEE User forums (www.eeeuser.com). You may even be able to search for the answers you're looking for - if they don't have the answers, the folks there are generally patient with new users.
A third Ubuntu-based option is Linux Mint (www.linuxmint.com). They should have a version out based on the new Ubuntu release soon. The one based on the current release should be solid as well. Again, the folks at the Eeeuser forum would be the most help sorting that out.
That's probably more info than you were looking for, but I hope it helps.


Setup was straightforward from a USB drive.
EasyPeasy Ubuntu doesn't play well with the webcam -- or it it does I haven't figured out how to get the two to work together.
Haven't tried the Ubuntu Netbook Remix version.