Help:
Mobile device:
Go to the main page
Click the Gear (You may have to click at the top of the page to see the gear)
Select "Getting Started Tour"
Access Notes Offline:
One of the premium features of evernote is "Access Notes Offline".
One of my friends says most of your notes are cached so you do not need to get a premium account for that.
In a test I searched for a common term in my notes. On my android tablet which I've had for a couple of years 75% of the notes were available offline (in airplane mode), while on my iPhone which was replaced about 4 months ago only 10% of the notes were available offline.

Links:
Search for evernote help

last updated 6 Jan 2012