How come I cant connect to wireless on ubuntu but mac is ok?

So lately I have been travelling around San Francisco. I keep running into situations like this:

1. Free Wifi is available, i.e. SFO airport or at starbucks


2. Can't connect to wifi using ubuntu (even if I restart etc). No modifications to the network manager whatsoever


3. When I boot into OS X, (I am dual booting ubuntu with mac os x on macbookpro), connecting to the same network is almost instantaneous and without any problems.

What could be the cause of this problem? Could it be that ubuntu's wireless connectivity is crappy or runnning ubuntu on macbookpro is not fully supported (I follow the guide completely on ubuntu's official pages).

Why am I experiencing this issue? How can I go about debugging it?

I am using the latest ubuntu 10.10.