I take the subway to work everyday. During that time period, I’m completely without mobile reception. I have an iPhone and AT&T and that doesn’t work in the subway tunnels.
So I was kind of excited when the NY Times announced that they were adding offline support for their iPhone app. I tried it on the subway today and it worked perfectly.
Now, I wish that Apple would add offline capability to the iPhone version of Safari so that I could do this with just a normal mobile Web site.
Oatmeal Stout - Justin Thorp's blog 
You mean the Metro? 😉
Thanks for the tip on the NYT app, I’ll have to give it another look!
I believe they support HTML5 databases perfectly, which work offline.
This iPhone web app is a good demo of that: http://brandonaaron.net/iphone/index.html#_about