In general follow guide by Lordikc. It refers to 2009.0 but get the 2009.1 dual iso instead.

There is built in LXDE choice during install, so you can skip most of the steps regarding task-sel for LXDE.

If you cannot connect to the Internet even though everything looks fine, follow the 2009.1 Errata

Wifi cannot be configured during the final step at install, reboot first, and use the network icon on bottom right.

If Wifi seems intermittent or slow, try setting your Wifi access point to the middle channel 6/7, and set the DHCP server on your router to give your Eee a static address.