As of this week, Gmail has reached perfection: You no longer have to be online to read or write messages. To get offline access, you first need to download and install a small program called Google Gears (except if you're using Google's Chrome browser, which comes with Gears built in).*
Then, after you enable Gmail's offline capability, the system will download two months of your most recent messages, which should take 30 minutes to an hour.
Now you're good to go.
GMAIL
It's all you really need...
