www.eeeuser.com - lots of good stuff there for experts and novices alike. Includes a growing WIKI.

You can permanently switch it to advanced mode (which really just loads a different xwindow manager, KDE) but I prefer the "easy mode" default. Just modifying it to have a custom start menu and task bar.

On the 4GB version, if you learn how to uninstall the apps you won't ever use (i.e. Thunderbird - I use webmail on the system, I don't need a mail client) and anything else will free up a lot more. But as mentioned, using an SDHC card (8GB right now, a few expensive 16GB cards available), a USB flash disk or USB hard drive gives you all the storage you need.