You will still be able to access the Start orb from the Windows button on keyboards or by hitting ctrl+esc on the keyboard. Additionally, if you "hover the mouse over the bottom left corner of the taskbar to bring up the Charms," you can mimic the Start orb function.
The Windows 8 Consumer Preview, aka beta, will be released soon, with a final version expected in the late summer of early fall.
Here is how the Windows 8 screen looks like without the Start Orb:












