Since LiLi 2.8 Beta, VMware Hypervisor ESXi 4.1 U1 (or later) is fully supported.
Follow steps 1 through 5 in LinuxLive USB Creator to create your USB key.
Then, you should have a ks.cfg file at the root of your USB key.
This ks.cfg contains all the settings needed to install ESXi from your USB key.
It is very important to note that IT WILL NOT WORK until you uncomment the "autopart" command.
This is a security to be sure you are aware that it will FORMAT the first disk of your host!